PID,Name,Title,PublicationType,ContentType,Language,Journal,JournalISSN,JournalEISSN,Status,Volume,Issue,HostPublication,StartPage,EndPage,Year,Edition,Pages,City,Publisher,Series,SeriesISSN,SeriesEISSN,ISBN,Urls,ISRN,DOI,ISI,PMID,ScopusId,NBN,LocalId,ArchiveNumber,Keywords,Categories,ResearchSubjects,Projects,Notes,Abstract,Opponents,Supervisors,Examiners,Patent,ThesisLevel,Credits,Programme,Subject,Uppsok,DefencePlace,DefenceLanguage,DefenceDate,CreatedDate,PublicationDate,LastUpdated,FullTextLink,Funder,NumberOfAuthors,ExternalCooperation,FridaLevel,PartOfThesis,PublicationSubtype,Conference,Term,ArticleId,Reviewed,FreeFulltext,SustainableDevelopment,Contributor "1274658","Mosyagin, Igor [igomo87] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (NUST MISTS, Russia);Lugovskoy, A. V. (NUST MISTS, Russia);Krasilnikov, O. M. (NUST MISTS, Russia; NUST MISTS, Russia);Vekilov, Yu. Kh. (NUST MISTS, Russia; NUST MISTS, Russia);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Reply to the comment by M. Mazdziarz on the article ""Ab initio calculations of pressure-dependence of high-order elastic constants using finite deformations approach"" [Computer Physics Communications 220 (2017) 20-30]","Artikel i tidskrift","Övrigt vetenskapligt","eng","Computer Physics Communications","0010-4655","1879-2944","published","235","","","295","296","2019","","","","ELSEVIER SCIENCE BV","","","","","","","10.1016/j.cpc.2018.06.007","000451491100028","","","urn:nbn:se:liu:diva-153493","","","Ab initio calculations; Elastic moduli; Pressure effects in solids and liquids; Finite deformations","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Research Council [2015-04391, 2014-4750]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]; Ministry of Education and Science of the Russian Federation [K2-2017-080, 14.Y26.31.0005]</p>","<p>Marcin Mazdziarz has published a comment on our recent paper by I. Mosyagin, A.V. Lugovskoy, O.M. Krasilnikov, Yu.Kh. Vekilov, S.I. Simak and L.A. Abrikosov titled ""Ab initio calculations of pressure dependence of high-order elastic constants using finite deformations approach"" [Computer Physics Communications 220 (2017)2030]. The author states that there are serious fundamental errors and flaws. In this reply we clarify all misunderstanding mentioned in the said comment. (C) 2018 Published by Elsevier B.V.</p>","","","","","","","","","","","","","2019-01-02","2019-01-02","2019-01-02","","","6","","1","","editorialMaterial","","","","false","","","" "1276262","Mockuté, Aurelija [aurmo58] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Palisaitis, Justinas [juspa01] [0000-0003-3203-7935] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Nedfors, Nils [nilne07] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Berastegui, P. (Uppsala Univ, Sweden);Broitman, Esteban [broes27] [0000-0003-3277-1945] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (SKF Res and Technol Dev Ctr, Netherlands);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Näslund, Lars-Åke [larna84] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Hultman, Lars [larhu75] [0000-0002-2837-3656] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Patscheider, J. (Evatec AG, Switzerland);Jansson, U. (Uppsala Univ, Sweden);Persson, Per O A [perpe25] [0000-0001-9140-6724] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Rosén, Johanna [johro07] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Synthesis and characterization of (Ti1-xAlx)B2+Delta thin films from combinatorial magnetron sputtering","Artikel i tidskrift","Refereegranskat","eng","Thin Solid Films","0040-6090","1879-2731","published","669","","","181","187","2019","","","","ELSEVIER SCIENCE SA","","","","","","","10.1016/j.tsf.2018.10.042","000453405600026","","","urn:nbn:se:liu:diva-153652","","","Titanium aluminium diboride; Thin films; Combinatorial sputtering; Mechanical properties; Phase decomposition","Keramteknik (20501)","","","<p>Funding Agencies|Knut and Alice Wallenbergs (KAW) Foundation [KAW 2015.0043]; Swedish Research Council [330-2014-6336, 2016-04412, 642-2013-8020]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]; Marie Sklodowska Curie Actions COFUND [INCA 600398]; Swedish Foundation for Strategic Research; Research Infrastructure Fellow Program [RIF 14-0074]; KAW Foundation</p>","<p>(Ti1-xAlx)B2+Delta films with a lateral composition gradient of x = [0.30-0.66] and Delta = [0.07-1.22] were deposited on an Al2O3 wafer by dual magnetron sputtering at 400 degrees C from sintered TiB2 and AlB2 targets. Composition analysis indicates that higher Ti:Al ratios favor overstoichiometry in B and a reduced incorporation of O. Transmission electron microscopy reveals distinctly different microstructures of Ti- and Al-rich compositions, with formation of characteristic conical growth features for the latter along with a lower degree of crystallinity and significantly less tissue phase from B segregation at the grain boundaries. For Al-rich films, phase separation into Ti- and Al-rich diboride nanometer-size domains is observed and interpreted as surface-initiated spinodal decomposition. The hardness of the films ranges from 14 to 28 GPa, where the higher values were obtained for the Ti-rich regions of the metal boride.</p>","","","","","","","","","","","","","2019-01-07","2019-01-07","2019-01-07","","","12","","1","","","","","","false","","","" "1281564","da Cunha, Wiliam Ferreira (Univ Brasilia, Brazil);de Oliveira Neto, Pedro Henrique (Univ Brasilia, Brazil);Ribeiro, Luiz Antonio [luiri41] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Univ Brasilia, Brazil);Magela e Silva, Geraldo (Univ Brasilia, Brazil)","Quasiparticle description of transition metal dichalcogenide nanoribbons","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","99","3","","","","2019","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.99.035405","000454766400013","","","urn:nbn:se:liu:diva-153960","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|CNPq; Brazilian Ministry of Planning, Development and Management [005/2016 DIPLA]; FAP-DF [0193.001766/2017, 0193.001511/2017, 0193.001662/2017, 0193.001694/2017]</p>","<p>An effective two-dimensional real-space model is developed to investigate the nature of charge distribution in nanoribbons of transition metal dichalcogenides. Our description is based on a lattice relaxation endowed tight-binding Hamiltonian with spin-orbit and Hubbard interactions, which is parameterized to describe molybdenum disulfide lattices. As our main finding, we observed that electron-phonon coupling induces the creation of quasiparticles such as polarons in the same fashion as observed in conducting polymers and graphene nanoribbons. These similarities suggest that the charge transport in transition metal dichalcogenides can also be mediated by quasiparticles, which is a fundamental aspect concerning the application of these structures in electronics. We determine a range of possible electron-phonon coupling that correctly describes the system and also the critical value where quasiparticle transport is present. Our findings may have profound consequences on the understanding of the transport mechanism of transition metal dichalcogenides nanoribbons.</p>","","","","","","","","","","","","","2019-01-22","2019-01-22","2019-01-22","","","4","","2","","","","","035405","false","","","" "1283673","Vorotilo, S. (Natl Univ Sci and Technol MISIS, Russia);Sidnov, K. (Natl Univ Sci and Technol MISIS, Russia; Russian Acad Sci, Russia);Mosyagin, I. Yu (Natl Univ Sci and Technol MISIS, Russia);Khvan, A. V (Natl Univ Sci and Technol MISIS, Russia);Levashov, E. A. (Natl Univ Sci and Technol MISIS, Russia);Patsera, E. I (Natl Univ Sci and Technol MISIS, Russia);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Natl Univ Sci and Technol MISIS, Russia)","Ab-initio modeling and experimental investigation of properties of ultra-high temperature solid solutions TaxZr1-xC","Artikel i tidskrift","Refereegranskat","eng","Journal of Alloys and Compounds","0925-8388","1873-4669","published","778","","","480","486","2019","","","","ELSEVIER SCIENCE SA","","","","","","","10.1016/j.jallcom.2018.11.219","000455179500053","","","urn:nbn:se:liu:diva-154089","","","UHTC; Phase diagram; DFT; SHS; Annealing","Metallurgi och metalliska material (20506)","","","<p>Funding Agencies|Ministry of Education and Science of the Russian Federation [14.Y26.31.0005, K2-2017-080]; Russian Science Foundation [17-79-10173]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]</p>","<p>Due to their high melting temperature, high-temperature oxidation resistance and outstanding mechanical properties, TaxZr1-xC solid solutions are promising ultra-high temperature ceramics (UHTC). However, accelerated knowledge-based development of UHTCs solid solutions requires reliable data regarding the properties of the solution phases in the whole interval of concentrations. At present, there are contradictory reports regarding the existence of the miscibility gap in Ta-Zr-C system at temperatures below 900 degrees C. In this work, we carry out ab-initio calculations of the thermodynamic properties of TaxZr1-xC alloys and demonstrate that the solid solutions should not decompose into TaC and ZrC end member compounds. We synthesize single-phase samples of TaxZr1-xC with compositions x = 0.9, 0.8, 0.6, and 0.3 by self-propagating high-temperature synthesis (SHS) and anneal the samples for 40 h. We do not observe any sign of the decomposition of the solid solution during the annealing, corroborating the conclusions obtained by theoretical simulations. (C) 2018 Elsevier B.V. All rights reserved.</p>","","","","","","","","","","","","","2019-01-29","2019-01-29","2019-01-29","","","7","","1","","","","","","false","","","" "1172548","Gharavi, Mohammad Amin [mohgh20] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Armiento, Rickard [ricar47] [0000-0002-5571-0814] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Max Planck Institute Eisenforsch GmbH, Germany);Eklund, Per [perek02] [0000-0003-1785-0864] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Theoretical study of phase stability, crystal and electronic structure of MeMgN2 (Me = Ti, Zr, Hf) compounds","Artikel i tidskrift","Refereegranskat","eng","Journal of Materials Science","0022-2461","1573-4803","published","53","6","","4294","4305","2018","","","","SPRINGER","","","","","","","10.1007/s10853-017-1849-0","000418294200030","","","urn:nbn:se:liu:diva-144130","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|European Research Council under the European Communitys Seventh Framework Programme (FP)/ERC [335383]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]; Swedish Foundation for Strategic Research (SSF) through the Future Research Leaders 5 and 6 programs; Knut and Alice Wallenberg foundation through the Academy Fellow program; Swedish Research Council (VR) [621-2012-4430, 2016-03365]; Swedish Research Council (VR) through International Career Grant [330-2014-6336]; Marie Sklodowska Curie Actions, Cofund [INCA 600398]; VR Grant [2016-04810]; Swedish e-Science Research Centre (SeRC)</p>","<p>Scandium nitride has recently gained interest as a prospective compound for thermoelectric applications due to its high Seebeck coefficient. However, ScN also has a relatively high thermal conductivity, which limits its thermoelectric efficiency and figure of merit (zT). These properties motivate a search for other semiconductor materials that share the electronic structure features of ScN, but which have a lower thermal conductivity. Thus, the focus of our study is to predict the existence and stability of such materials among inherently layered equivalent ternaries that incorporate heavier atoms for enhanced phonon scattering and to calculate their thermoelectric properties. Using density functional theory calculations, the phase stability of TiMgN2, ZrMgN2 and HfMgN2 compounds has been calculated. From the computationally predicted phase diagrams for these materials, we conclude that all three compounds are stable in these stoichiometries. The stable compounds may have one of two competing crystal structures: a monoclinic structure (LiUN2 prototype) or a trigonal superstructure (NaCrS2 prototype; RmH). The band structure for the two competing structures for each ternary is also calculated and predicts semiconducting behavior for all three compounds in the NaCrS2 crystal structure with an indirect band gap and semiconducting behavior for ZrMgN2 and HfMgN2 in the monoclinic crystal structure with a direct band gap. Seebeck coefficient and power factors are also predicted, showing that all three compounds in both the NaCrS2 and the LiUN2 structures have large Seebeck coefficients. The predicted stability of these compounds suggests that they can be synthesized by, e.g., physical vapor deposition.</p>","","","","","","","","","","","","","2018-01-10","2018-01-10","2018-02-12","http://liu.diva-portal.org/smash/get/diva2:1172548/FULLTEXT01.pdf","","4","","1","","","","","","false","","","" "1176706","Sangiovanni, Davide [davsa82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Ruhr University of Bochum, Germany);Mei, A. B. (University of Illinois, IL 61801 USA; Cornell University, NY 14853 USA);Edström, Daniel [daned22] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Hultman, Lars [larhu75] [0000-0002-2837-3656] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Chirita, Valeriu [valch35] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Petrov, Ivan [ivape26] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Illinois, USA);Greene, Joseph E [josgr17] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Illinois, USA)","Effects of surface vibrations on interlayer mass transport: Ab initio molecular dynamics investigation of Ti adatom descent pathways and rates from TiN/TiN(001) islands","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","97","3","","","","2018","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.97.035406","000419320900005","","","urn:nbn:se:liu:diva-144438","","","","Teoretisk kemi (10407)","","","<p>Funding Agencies|Olle Engkvist Foundation [2016/408]; Swedish Research Council (VR) Linkoping Linnaeus Initiative (LiLi-NFM) [2008-6572, 2014-5790, 2013-4018]; Swedish Government Strategic Research Area Grant in Materials Science on Advanced Functional Materials (Swedenapos;s innovation agency VINNOVA) [MatLiU 2009-00971]; Knut and Alice Wallenberg Foundation [2011.0094]</p>","<p>We carried out density-functional ab initio molecular dynamics (AIMD) simulations of Ti adatom (Ti-ad ) migration on, and descent from, square TiN(100) epitaxial islands on TiN(001) at temperatures (T) ranging from 1200 to 2400 K. Adatom-descent energy barriers determined via ab initio nudged-elastic-band calculations at 0 Kelvin suggest that Ti interlayer transport on TiN(001) occurs essentially exclusively via direct hopping onto a lower layer. However, AIMD simulations reveal comparable rates for Ti-ad descent via direct hopping vs push-out/exchange with a Ti island-edge atom for T amp;gt;= 1500 K. We demonstrate that this effect is due to surface vibrations, which yield considerably lower activation energies at finite temperatures by significantly modifying the adatom push-out/exchange reaction pathway.</p>","","","","","","","","","","","","","2018-01-23","2018-01-23","2018-02-12","http://liu.diva-portal.org/smash/get/diva2:1176706/FULLTEXT01.pdf","","7","","2","","","","","035406","false","","","" "1183657","Mozafari, Elham [elhmo04] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Max Planck Inst Eisenforsch GmbH, Germany);Belov, Maxim P. (NUST MISIS, Russia);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Effect of the lattice dynamics on the electronic structure of paramagnetic NiO within the disordered local moment picture","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","97","3","","","","2018","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.97.035152","000423347500001","","","urn:nbn:se:liu:diva-145131","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Research Council (VR) [2015-04391, 621-2011-4417, 330-2014-6336]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005, K2-2017-080]; Marie Sklodowska Curie Actions [INCA 600398]; Swedish Foundation for Strategic Research (SSF) through the future research leaders 6 program; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFOMatLiU) [2009 00971]</p>","<p>Using the disordered local moments approach in combination with the ab initio molecular dynamics method, we simulate the behavior of a paramagnetic phase of NiO at finite temperatures to investigate the effect of magnetic disorder, thermal expansion, and lattice vibrations on its electronic structure. In addition, we study its lattice dynamics. We verify the reliability of our theoretical scheme via comparison of our results with available experiment and earlier theoretical studies carried out within static approximations. We present the phonon dispersion relations for the paramagnetic rock-salt (B1) phase of NiO and demonstrate that it is dynamically stable. We observe that including the magnetic disorder to simulate the paramagnetic phase has a small yet visible effect on the band gap. The amplitude of the local magnetic moment of Ni ions from our calculations for both antiferromagnetic and paramagnetic phases agree well with other theoretical and experimental values. We demonstrate that the increase of temperature up to 1000 K does not affect the electronic structure strongly. Taking into account the lattice vibrations and thermal expansion at higher temperatures have amajor impact on the electronic structure, reducing the band gap from similar to 3.5 eV at 600 K to similar to 2.5 eV at 2000 K. We conclude that static lattice approximations can be safely employed in simulations of the paramagnetic state of NiO up to relatively high temperatures (similar to 1000 K), but as we get closer to the melting temperature vibrational effects become quite large and therefore should be included in the calculations.</p>","","","","","","","","","","","","","2018-02-19","2018-02-19","2018-03-09","http://liu.diva-portal.org/smash/get/diva2:1183657/FULLTEXT01.pdf","","4","","2","","","","","035152","false","","","" "1182444","Rivera Vila, Henrique Vieira (Univ Brasilia, Brazil);Ribeiro, Luiz Antonio [luiri41] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Univ Brasilia, Brazil);Machado de Macedo, Luiz Guilherme (Fed Univ Para, Brazil);Gargano, Ricardo (Univ Brasilia, Brazil)","On the Angular Distribution of the H+Li-2 Cross Sections: a Converged Time-Independent Quantum Scattering Study","Artikel i tidskrift","Refereegranskat","eng","Scientific Reports","2045-2322","2045-2322","published","8","","","","","2018","","","","NATURE PUBLISHING GROUP","","","","","","","10.1038/s41598-018-19233-0","000422739300007","29348595","","urn:nbn:se:liu:diva-145143","","","","Annan fysik (10399)","","","<p>Funding Agencies|CNPQ; Brazilian Ministry of Planning, Budget and Management [DIPLA 005/2016]; FAPDF [0193.000942/2015]</p>","<p>A thorough time-independent quantum scattering study is performed on a benchmark potential energy surface for the H+Li-2 reaction at the fundamental electronic state. Integral and differential cross sections are calculated along with thermal rate coefficients until convergence is reached. Our findings show that vibrational and rotational excitations of the reactant hinder reactivity, though for the latter a considerable reaction promotion was spotted as we increase the reactant rotational quantum number until the critical value of j = 4. Such a promotion then begins to retract, eventually becoming an actual inhibition for larger j. In a straightforward manner, the concept of time-independent methods implemented in this study allowed this accurate state-to-state analysis. Furthermore, a nearly isotropic behaviour of the scattering is noted to take place from the angular point of view. Remarkably, our computational protocol is ideally suited to yield converged thermal rate coefficients, revealing a non-Arrhenius pattern and showing that J-shifting approach fails to describe this particular reaction. Our results, when compared to previous and independent ones, reinforce the latest theoretical reference for future validation in the experimental field.</p>","","","","","","","","","","","","","2018-02-13","2018-02-13","2018-03-09","http://liu.diva-portal.org/smash/get/diva2:1182444/FULLTEXT01.pdf","","4","","1","","","","","1044","false","","","" "1181677","Klarbring, Johan [johkl85] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Nature of the octahedral tilting phase transitions in perovskites: A case study of CaMnO3","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","97","2","","","","2018","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.97.024108","000423118400003","","","urn:nbn:se:liu:diva-144883","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Research Council (VR) [2014-4750]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]; CeNano at Linkoping University</p>","<p>The temperature-induced antiferrodistortive (AFD) structural phase transitions in CaMnO3, a typical perovskite oxide, are studied using first-principles density functional theory calculations. These transitions are caused by tilting of the MnO6 octahedra that are related to unstable phonon modes in the high-symmetry cubic perovskite phase. Transitions due to octahedral tilting in perovskites normally are believed to fit into the standard soft-mode picture of displacive phase transitions. We calculate phonon-dispersion relations and potential-energy landscapes as functions of the unstable phonon modes and argue based on the results that the phase transitions are better described as being of order-disorder type. This means that the cubic phase emerges as a dynamical average when the system hops between local minima on the potential-energy surface. We then perform ab initio molecular dynamics simulations and find explicit evidence of the order-disorder dynamics in the system. Our conclusions are expected to be valid for other perovskite oxides, and we finally suggest how to predict the nature (displacive or order-disorder) of the AFD phase transitions in any perovskite system.</p>","","","","","","","","","","","","","2018-02-09","2018-02-09","2018-03-09","http://liu.diva-portal.org/smash/get/diva2:1181677/FULLTEXT01.pdf","","2","","2","","","","","024108","false","","","" "1182425","Xia, Chao [chaxi72] (Linköpings universitet [276], Tekniska fakulteten [872902]) (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]);Tal, Alexey [aleta94] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Natl Univ Sci and Technol MISIS, Russia);Johansson, Leif [leijo19] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Olovsson, Weine [weiol14] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Linköpings universitet [276], Nationellt superdatorcentrum (NSC) [16051]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Virojanadara, Chariya [chavi32] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Effects of rhenium on graphene grown on SiC(0001)","Artikel i tidskrift","Refereegranskat","eng","Journal of Electron Spectroscopy and Related Phenomena","0368-2048","1873-2526","published","222","","","117","121","2018","","","","Elsevier","","","","","","","10.1016/j.elspec.2017.07.006","000423638100016","","","urn:nbn:se:liu:diva-145152","","","Rhenium; Graphene; Photoelectron spectroscopy; Core-level shift; Ab initio density functional theory","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Knut and Alice Wallenberg Foundation [2012.0083]; Knut and Alice Wallenberg Foundation through CoTXS; Swedish Foundation or Strategic Research (SSF) program SRL Grant [10-0026]; Swedish Research Council (VR) [2015-04391]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [200900971]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Swedish Research Council [621-2011-4252]</p>","<p>We study the effects of Rhenium (Re) deposited on epitaxial monolayer graphene grown on SiC(0001) and after subsequent annealing at different temperatures, by performing high resolution photoelectron spectroscopy (PES) and angle resolved photoelectron spectroscopy (ARPES). The graphene-Re system is found to be thermally stable. While no intercalation or chemical reaction of the Re is detected after deposition and subsequent annealing up to 1200 degrees C, a gradual decrease in the binding energy of the Re 4f doublet is observed. We propose that a larger mobility of the Re atoms with increasing annealing temperature and hopping of Re atoms between different defective sites on the graphene sample could induce this decrease of Re 4f binding energy. This is corroborated by first principles density functional theory (DFT) calculations of the Re core-level binding energy shift. No change in the doping or splitting of the initial monolayer graphene electronic band structure is observed after Re deposition and annealing up to 1200 degrees C, only a broadening of the bands. (C) 2017 Elsevier B.V. All rights reserved.</p>","","","","","","","","","","","","","2018-02-13","2018-02-13","2018-03-19","","","6","","1","","","","","","true","","","" "1192456","Spektor, Kristina (ESRF, France);Crichton, Wilson A. (ESRF, France);Konar, Sumit (Univ Edinburgh, Scotland; Univ Edinburgh, Scotland);Filippov, Stanislav [stafi86] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Klarbring, Johan [johkl85] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Haussermann, Ulrich (Stockholm Univ, Sweden)","Unraveling Hidden Mg-Mn-H Phase Relations at High Pressures and Temperatures by in Situ Synchrotron Diffraction","Artikel i tidskrift","Refereegranskat","eng","Inorganic Chemistry","0020-1669","1520-510X","published","57","3","","1614","1622","2018","","","","AMER CHEMICAL SOC","","","","","","","10.1021/acs.inorgchem.7b02968","000424730800075","29323885","","urn:nbn:se:liu:diva-145773","","","","Oorganisk kemi (10404)","","","<p>Funding Agencies|Swedish Research Council (VR) [2013-4690, 2014-4750]; Swedish Government Strategic Research Area Grant in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]; Carl Tryggers Stiftelse (CTS) for Vetenskaplig Forskning [16:198]</p>","<p>The MgMnH system was investigated by in situ high pressure studies of reaction mixtures MgH2MnH2. The formation conditions of two complex hydrides with composition Mg3MnH7 were established. Previously known hexagonal Mg3MnH7 (h-Mg3MnH7) formed at pressures 1.52 GPa and temperatures between 480 and 500 degrees C, whereas an orthorhombic form (o-Mg3MnH7) was obtained at pressures above 5 GPa and temperatures above 600 degrees C. The crystal structures of the polymorphs feature octahedral [Mn(I)H-6](5) complexes and interstitial H-. Interstitial H- is located in trigonal bipyramidal and square pyramidal interstices formed by Mg2+ ions in h- and o-Mg3MnH7, respectively. The hexagonal form can be retained at ambient pressure, whereas the orthorhombic form upon decompression undergoes a distortion to monoclinic Mg3MnH7 (m-Mg3MnH7). The structure elucidation of o- and m-Mg3MnH7 was aided by first-principles density functional theory (DFT) calculations. Calculated enthalpy versus pressure relations predict m- and o-Mg3MnH7 to be more stable than h-Mg3MnH7 above 4.3 GPa. Phonon calculations revealed o-Mg3MnH7 to be dynamically unstable at pressures below 5 GPa, which explains its phase transition to m-Mg3MnH7 on decompression. The electronic structure of the quenchable polymorphs h- and m-Mg3MnH7 is very similar. The stable 18-electron complex [MnH6](5-) is mirrored in the occupied states, and calculated band gaps are around 1.5 eV. The study underlines the significance of in situ investigations for mapping reaction conditions and understanding phase relations for hydrogen-rich complex transition metal hydrides.</p>","","","","","","","","","","","","","2018-03-22","2018-03-22","2018-03-22","","","7","","2","","","","","","false","","","" "1184538","Ribeiro Jr, Luiz Antonio [luiri41] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Institute of Physics, University of Brasίlia, Brasίlia, Brazil);da Silva, Gesiel Gomes (Institute of Physics, University of Brasίlia, Brasίlia, Brazil; Goias Federal Institute of Science and Technology, IFG, Luziânia, Brazil);de Sousa Jr, Rafael Timoteo (Department of Electrical Engineering, University of Brasίlia, Brasίlia, Brazil);de Almeida Fonseca, Antonio Luciano (Institute of Physics, University of Brasίlia, Brasίlia, Brazil);da Cunha, Wiliam Ferreira (Institute of Physics, University of Brasίlia, Brasίlia, Brazil);Magela e Silva, Geraldo (Institute of Physics, University of Brasίlia, Brasίlia, Brazil)","Spin-Orbit Effects on the Dynamical Properties of Polarons in Graphene Nanoribbons","Artikel i tidskrift","Refereegranskat","eng","Scientific Reports","2045-2322","2045-2322","published","8","","","","","2018","","","","Nature Publishing Group","","","","","","","10.1038/s41598-018-19893-y","000423508900085","29382862","2-s2.0-85041342699","urn:nbn:se:liu:diva-145247","","","","Annan fysik (10399)","","","<p>Funding Agencies|CNPq; CAPES; FAP-DF; FINATEC; Brazilian Ministry of Planning, Development and Management [005/2016 DIPLA, 11/2016 SEST]; DPGU - Brazilian Union Public Defender [066/2016]; FAP-DF [0193.000.942/2015, 0193.001343/2016]; IFG</p>","<p>The dynamical properties of polarons in armchair graphene nanoribbons (GNR) is numerically investigated in the framework of a two-dimensional tight-binding model that considers spin-orbit (SO) coupling and electron-lattice (e-l) interactions. Within this physical picture, novel polaron properties with no counterparts to results obtained from conventional tight-binding models are obtained. Our findings show that, depending on the systems width, the presence of SO coupling changes the polarons charge localization giving rise to different degrees of stability for the charge carrier. For instance, the joint action of SO coupling and e-l interactions could promote a slight increase on the charge concentration in the center of the lattice deformation associated to the polaron. As a straightforward consequence, this process of increasing stability would lead to a depreciation in the polarons motion by decreasing its saturation velocity. Our finds are in good agreement with recent experimental investigations for the charge localization in GNR, mostly when it comes to the influence of SO coupling. Moreover, the contributions reported here provide a reliable method for future works to evaluate spin-orbit influence on the performance of graphene nanoribbons.</p>","","","","","","","","","","","","","2018-02-21","2018-02-21","2018-03-23","http://liu.diva-portal.org/smash/get/diva2:1184538/FULLTEXT01.pdf","","6","","1","","","","","1914","true","","","" "1192479","Davidsson, Joel [joeda01] [0000-0002-5349-3318] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Ivády, Viktor [vikiv58] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Hungarian Acad Sci, Hungary);Armiento, Rickard [ricar47] [0000-0002-5571-0814] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Nguyen, Son Tien [nguso90] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Gali, Adam (Hungarian Acad Sci, Hungary; Budapest Univ Technol and Econ, Hungary);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Natl Univ Sci and Technol MISIS, Russia)","First principles predictions of magneto-optical data for semiconductor point defect identification: the case of divacancy defects in 4H-SiC","Artikel i tidskrift","Refereegranskat","eng","New Journal of Physics","1367-2630","1367-2630","published","20","","","","","2018","","","","IOP PUBLISHING LTD","","","","","","","10.1088/1367-2630/aaa752","000425349000003","","","urn:nbn:se:liu:diva-145768","","","point defects; zero-phonon line; hyperfine field; DFT; convergence; SiC","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Government Strategic Research Areas in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; Swedish e-Science Centre (SeRC); Centre in Nano science and Nanotechnology (CeNano); Knut&amp;Alice Wallenberg Foundation New States of Matter (COTXS); Swedish Research Council (VR) [2015-04391, 2016-04810, 2016-04068]; Linkoping University [LiU-2015-00017-60]; Swedish National Infrastructure for Computing Grants [SNIC 001/12-275, SNIC 2013/1-331, SNIC 2016/1-528]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005, K2-2017-080]; US Department of Energy, Office of Science, Office of Basic Energy Sciences [DE-AC02-06CH11357]; National Research Development and Innovation Office of Hungary within the Quantum Technology National Excellence Program [2017-1.2.1-NKP-2017-00001]</p>","<p>Study and design of magneto-optically active single point defects in semiconductors are rapidly growing fields due to their potential in quantum bit (qubit) and single photon emitter applications. Detailed understanding of the properties of candidate defects is essential for these applications, and requires the identification of the defects microscopic configuration and electronic structure. In multicomponent semiconductors point defects often exhibit several non-equivalent configurations of similar but different characteristics. The most relevant example of such point defect is the divacancy in silicon carbide, where some of the non-equivalent configurations implement room temperature qubits. Here, we identify four different configurations of the divacancy in 4H-SiC via the comparison of experimental measurements and results of first-principle calculations. In order to accomplish this challenging task, we carry out an exhaustive numerical accuracy investigation of zero-phonon line and hyperfine coupling parameter calculations. Based on these results, we discuss the possibility of systematic quantum bit search.</p>","","","","","","","","","","","","","2018-03-22","2018-03-22","2018-04-13","http://liu.diva-portal.org/smash/get/diva2:1192479/FULLTEXT01.pdf","","6","","1","","","","","023035","false","","","" "1192905","Skripnyak, Natalia [natsk33] [0000-0003-1634-5882] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Ponomareva, A. V. (Natl Univ Sci and Technol MISIS, Russia);Belov, M. P. (Natl Univ Sci and Technol MISIS, Russia);Abrikosov, Igor A. [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Ab initio calculations of elastic properties of alloys with mechanical instability: Application to BCC Ti-V alloys","Artikel i tidskrift","Refereegranskat","eng","Materials & design","0264-1275","1873-4197","published","140","","","357","365","2018","","","","Elsevier","","","","","https://www.ifm.liu.se/theomod/theophys/publications/fulltexts/artikel-med-forsattsblad-(002).pdf","","10.1016/j.matdes.2017.11.071","000424943900037","","","urn:nbn:se:liu:diva-145445","","","Efficient first-principal simulations; Elastic moduli; Substitutional disorder; Ti-V alloys; Mechanical stabilization","Annan materialteknik (20599)","","","<p>Funding Agencies|Ministry of Education and Science of the Russian Federation [K2-2016-013, 211]; Swedish Research Council [2015-04391]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]</p>","<p>Considering Ti-V alloys with the body-centered cubic crystal lattice, a system with mechanical instability for Tirich alloys, we calculate their elastic properties using Projector Augmented Wave method and the exact muffin tin orbital method in a complete interval of V concentrations. The substitutional disorder is modeled using the special quasi-random structures technique and the coherent potential approximation. The efficiency and accuracy of the simulation techniques is analyzed, and a strategy for efficient high-throughput calculations of elastic properties of disordered alloys is proposed. Dependences of the single crystal elastic moduli on V concentration and a set ofmechanical characteristics of polycrystalline alloys are presented and discussed. The effect of V content on themechanical stabilization of the bcc Ti-V alloys is investigated. In agreement with experiment, we find that titanium-rich alloys are mechanically unstable, however the alloys becomemechanically stablewith increasing content of V in the system. We observe a nonlinear dependence of the alloys Youngs moduli in a vicinity of the mechanical stabilization and suggest that this effect can be used to design alloys with low values of the elastic moduli. (C) 2017 Elsevier Ltd. All rights reserved.</p>","","","","","","","","","","","","","2018-03-23","2018-03-23","2018-04-19","http://liu.diva-portal.org/smash/get/diva2:1192905/FULLTEXT01.pdf","","4","","1","","","","","","false","true","","" "1199481","Bugaev, K. A. (Bogolyubov Inst Theoret Phys, Ukraine);Sagun, V. V. (Bogolyubov Inst Theoret Phys, Ukraine; Univ Lisbon, Portugal);Ivanytskyi, A. I. (Bogolyubov Inst Theoret Phys, Ukraine);Yakimenko, Iryna P. [iryya88] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Nikonov, E. G. (JINR, Russia);Taranenko, A. V. (Natl Res Nucl Univ MEPhI, Russia);Zinovjev, G. M. (Bogolyubov Inst Theoret Phys, Ukraine)","Going beyond the second virial coefficient in the hadron resonance gas model","Artikel i tidskrift","Refereegranskat","eng","Nuclear Physics A","0375-9474","1873-1554","published","970","","","133","155","2018","","","","ELSEVIER SCIENCE BV","","","","","","","10.1016/j.nuclphysa.2017.11.008","000427447200010","","","urn:nbn:se:liu:diva-147158","","","Hadron resonance gas model; Hard-core repulsion; Induced surface tension","Annan fysik (10399)","","","<p>Funding Agencies|program ""Nuclear matter under extreme conditions""; Fundacao para a Ciencia e a Tecnologia (FCT), Portugal [UID/FIS/00099/2013]; ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum fur Schwerionenforschung, Darmstadt, Germany; Ministry of Science and Education of the Russian Federation [3.3380.2017/4.6]; National Research Nuclear University ""MEPhI"" in the framework of the Russian Academic Excellence Project [02.a03.21.0005]</p>","<p>We develop a novel formulation of the hadron resonance gas model which, besides a hard-core repulsion, explicitly accounts for the surface tension induced by the interaction between the particles. Such an equation of state allows us to go beyond the Van der Waals approximation for any number of different hard-core radii. A comparison with the Carnahan Starling equation of state shows that the new model is valid for packing fractions 0.2-0.22, while the usual Van der Waals model is inapplicable at packing fractions above 0.1-0.11. Moreover, it is shown that the equation of state with induced surface tension is softer than the one of hard spheres and remains causal at higher particle densities. The great advantage of our model is that there are only two equations to be solved and neither their number nor their form depend on the values of the hard-core radii used for different hadronic resonances. Such an advantage leads to a significant mathematical simplification compared to other versions of truly multi-component hadron resonance gas models. Using this equation of state we obtain a high-quality fit of the ALICE hadron multiplicities measured at the center-of-mass energy 2.76 TeV per nucleon and we find that the dependence of chi(2)/ndf on the temperature has a single global minimum in the traditional hadron resonance gas model with the multi-component hard-core repulsion. Also we find two local minima of chi(2)/ndf in the model in which the proper volume of each hadron is proportional to its mass. However, it is shown that in the latter model a second local minimum located at higher temperatures always appears far above the limit of its applicability. (C) 2017 Elsevier B.V. All rights reserved.</p>","","","","","","","","","","","","","2018-04-20","2018-04-20","2018-04-20","","","7","","1","","","","","","false","","","" "1199726","Tasnadi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Natl Univ Sci and Technol MISIS, Russia);Wang, Fei [feiwa67] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Saarland Univ, Germany);Odén, Magnus [magod41] [0000-0002-2286-5588] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Natl Univ Sci and Technol MISIS, Russia)","Thermal expansion of quaternary nitride coatings","Artikel i tidskrift","Refereegranskat","eng","Journal of Physics: Condensed Matter","0953-8984","1361-648X","published","30","13","","","","2018","","","","IOP PUBLISHING LTD","","","","","","","10.1088/1361-648X/aab0b8","000426931800001","29460845","","urn:nbn:se:liu:diva-147079","","","thermal expansion; Ti-Al-N systems; quaternary alloys","Energiteknik (20304)","","","<p>Funding Agencies|Swedish Foundation for Strategic Research (SSF) program SRL Grant [10-0026, 621-2012-4401]; Vinnova [2016-05156]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; Vinnova (M-ERA.NET project: Multi-scale computational-driven design of novel hard nanostructured Coatings-MC2); Ministry of Education and Science of the Russian Federation [14.Y26.31.0005, K2-2017-080]; Erasmus Mundus Joint European Doctoral Programme DocMASE</p>","<p>The thermal expansion coefficient of technologically relevant multicomponent cubic nitride alloys are predicted using the Debye model with ab initio elastic constants calculated at 0 K and an isotropic approximation for the Gruneisen parameter. Our method is benchmarked against measured thermal expansion of TiN and Ti(1-x)AlxN as well as against results of molecular dynamics simulations. We show that the thermal expansion coefficients of Ti(1-x-y)XyAlxN (X = Zr, Hf, Nb, V, Ta) solid solutions monotonously increase with the amount of alloying element X at all temperatures except for Zr and Hf, for which they instead decrease for y greater than or similar to 0.5.</p>","","","","","","","","","","","","","2018-04-22","2018-04-22","2018-04-22","","","4","","1","","","","","135901","false","","","" "1206665","Lischka, Matthias (Tech Univ Munich, Germany; Deutsch Museum, Germany);Fritton, Massimo (Tech Univ Munich, Germany; Deutsch Museum, Germany);Eichhorn, Johanna (Tech Univ Munich, Germany; Deutsch Museum, Germany);Vyas, Vijay S. (Max Planck Inst Solid State Res, Germany; Marquette Univ, WI 53233 USA);Strunskus, Thomas (Christian Albrechts Univ Kiel, Germany);Lotsch, Bettina V. (Max Planck Inst Solid State Res, Germany; Nanosyst Initiat Munich, Germany; Ctr NanoSci, Germany; Univ Munich LMU, Germany);Björk, Jonas [jonbj66] [0000-0002-1345-0006] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Heckl, Wolfgang M. (Tech Univ Munich, Germany; Deutsch Museum, Germany; Nanosyst Initiat Munich, Germany; Ctr NanoSci, Germany);Lackinger, Markus (Tech Univ Munich, Germany; Deutsch Museum, Germany; Nanosyst Initiat Munich, Germany; Ctr NanoSci, Germany)","On-Surface Polymerization of 1,6-Dibromo-3,8-diiodpyrene-A Comparative Study on Au(111) Versus Ag(111) by STM, XPS, and NEXAFS","Artikel i tidskrift","Refereegranskat","eng","The Journal of Physical Chemistry C","1932-7447","1932-7455","published","122","11","","5967","5977","2018","","","","AMER CHEMICAL SOC","","","","","","","10.1021/acs.jpcc.7b10403","000428356700016","","","urn:nbn:se:liu:diva-147413","","","","Oorganisk kemi (10404)","","","<p>Funding Agencies|The excellence cluster Nanosystems Initiative Munich; Max Planck Society</p>","<p>The surface chemistry of 1,6-dibromo-3,8-diiodopyrene (Br2I2Py) is comparatively studied on Au(111) versus Ag(111) surfaces under ultrahigh vacuum conditions by a combination of high-resolution scanning tunneling microscopy (STM) and X-ray spectroscopy. The chemical state of the molecular networks, that is, the dehalogenation and the possible formation of organometallic intermediates, is assessed by X-ray photoelectron spectroscopy. In addition, pyrene tilt angles are quantified by carbon K-edge near edge X-ray absorption fine structure experiments. Upon room-temperature (RT) deposition of Br2I2Py onto Au(111), only partial deiodination was found, and STM revealed the coexistence of ordered arrangements of both intact Br2I2Py molecules and organometallic dimers as well as few larger aggregates. Further annealing to 100 C triggered full deiodination followed by the formation of organometallic chains of otherwise still brominated molecules. By contrast, on Ag(111), iodine is fully and bromine is partly dissociated upon RT deposition of Br2I2Py. The initially disordered organometallic aggregates can be reorganized into more ordered structures by mild annealing at 125 degrees C. Yet, the conversion of the organometallic intermediates into well-defined cross-linked quasi 2D covalent networks was neither possible on Au(111) nor on Ag(111). This is attributed to the large steric hindrance in the covalently linked adsorbed state.</p>","","","","","","","","","","","","","2018-05-17","2018-05-17","2018-05-17","","","9","","1","","","","","","false","","","" "1188371","Edström, Daniel [daned22] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Sangiovanni, Davide [davsa82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Ruhr Univ Bochum, Germany);Hultman, Lars [larhu75] [0000-0002-2837-3656] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Petrov, Ivan [ivape26] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Univ Illinois, IL 61801 USA);Greene, Joseph E [josgr17] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Univ Illinois, IL 61801 USA);Chirita, Valeriu [valch35] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Elastic properties and plastic deformation of TiC- and VC-based alloys","Artikel i tidskrift","Refereegranskat","eng","Acta Materialia","1359-6454","1873-2453","published","144","","","376","385","2018","","","","PERGAMON-ELSEVIER SCIENCE LTD","","","","","","","10.1016/j.actamat.2017.10.047","000424067100035","","","urn:nbn:se:liu:diva-145470","","","Carbides; Density functional theory; Elastic properties; Ductility; Toughness","Annan materialteknik (20599)","","","<p>Funding Agencies|Swedish Research Council (VR) Linkoping Linnaeus Initiative LiLi-NFM [2008-6572]; Swedish Government Strategic Research Area Grant in Materials Science on Advanced Functional Materials (Grant SFO-Mat-LiU) [2009 00971]; Olle Engkvist Foundation</p>","<p>Transition-metal (TM) carbides are an important class of hard, protective coating materials; however, their brittleness often limits potential applications. We use density functional theory to investigate the possibility of improving ductility by forming pseudobinary cubic (MMC)-M-1-C-2 alloys, for which M-1 = Ti or V and M-2 = W or Mo. The alloying elements are chosen based on previous results showing improved ductility of the corresponding pseudobinary nitride alloys with respect to their parent compounds. While commonly-used empirical criteria do not indicate enhanced ductility in the carbide alloys, calculated stress/strain curves along known slip systems, supported by electronic structure analyses, indicate ductile behavior for VMoC. As VMoC layers are sheared along the 1 (1) over bar0 direction on {111} planes, the stress initially increases linearly up to a yield point where the accumulated stress is partially dissipated. With further increase in strain, the stress increases again until fracture occurs. A similar mechanical behavior is observed for the corresponding TM nitride VMoN, known to be a ductile ceramic material [1]. Thus, our results show that VMoC is a TM carbide alloy which may be both hard and ductile, i.e. tough. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.</p>","","","","","","","","","","","","","2018-03-07","2018-03-07","2018-05-18","","","6","","2","","","","","","false","","","" "1209542","Ribeiro, Luiz Antonio [luiri41] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Univ Brasilia, Brazil);Monteiro, Fabio Ferreira (Univ Brasilia, Brazil);Enders, Bernhard Georg (Univ Brasilia, Brazil);de Almeida Fonseca, Antonio Luciano (Univ Brasilia, Brazil);Magela e Silva, Geraldo (Univ Brasilia, Brazil);da Cunha, Wiliam Ferreira (Univ Brasilia, Brazil)","Dynamic Formation of Bipolaron-Exciton Complexes in Conducting Polymers","Artikel i tidskrift","Refereegranskat","eng","Journal of Physical Chemistry A","1089-5639","1520-5215","published","122","15","","3866","3872","2018","","","","AMER CHEMICAL SOC","","","","","","","10.1021/acs.jpca.7b12185","000430783700018","29608859","","urn:nbn:se:liu:diva-147933","","","","Annan kemi (10499)","","","<p>Funding Agencies|Brazilian Research Council CNPq; Brazilian Research Council CAPES; Brazilian Research Council FAP-DF; Brazilian Research Council FINATEC; CENAPAD-SP; FAP-DF [193.001.234/2016, 193.001.556/2017, 0193.000.942/2015]; Brazilian Ministry of Planning, Budget and Management [DIPLA 005/2016]</p>","<p>The recombination dynamics of two oppositely charged bipolarons within a single polymer chain is numerically studied in the scope of a one-dimensional tight-binding model that considers electron electron and electron-phonon (e-ph) interactions. By scanning among values of e-ph coupling and electric field, novel channels for the bipolaron recombination were yielded based on the interplay between these two parameters. The findings point to the formation of a compound species formed from the coupling between a bipolaron and an exciton. Depending on the electric field and e-ph coupling strengths, the recombination mechanism may yield two distinct products: a trapped (and almost neutral) or a moving (and partially charged) bipolaron-exciton. These results might enlighten the understanding of the electroluminescence processes in organic light-emitting devices.</p>","","","","","","","","","","","","","2018-05-23","2018-05-23","2018-05-23","","","6","","2","","","","","","false","","","" "1209624","Karlsson, H. [n/a] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Yakymenko, Iryna [iryya88] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Berggren, Karl-Fredrik [karbe79] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Nature of magnetization and lateral spin-orbit interaction in gated semiconductor nanowires","Artikel i tidskrift","Refereegranskat","eng","Journal of Physics: Condensed Matter","0953-8984","1361-648X","published","30","21","","","","2018","","","","IOP PUBLISHING LTD","","","","","","","10.1088/1361-648X/aabc15","000431423400002","29623898","","urn:nbn:se:liu:diva-147904","","","quantum wire; quantum transport; lateral spin-orbit interaction; modelling; Hartree-Fock method","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Carl Trygger Science Foundation of Sweden</p>","<p>Semiconductor nanowires are interesting candidates for realization of spintronics devices. In this paper we study electronic states and effects of lateral spin-orbit coupling (LSOC) in a one-dimensional asymmetrically biased nanowire using the Hartree-Fock method with Dirac interaction. We have shown that spin polarization can be triggered by LSOC at finite source-drain bias,as a result of numerical noise representing a random magnetic field due to wiring or a random background magnetic field by Earth magnetic field, for instance. The electrons spontaneously arrange into spin rows in the wire due to electron interactions leading to a finite spin polarization. The direction of polarization is, however, random at zero source-drain bias. We have found that LSOC has an effect on orientation of spin rows only in the case when source-drain bias is applied.</p>","","","","","","","","","","","","","2018-05-23","2018-05-23","2018-05-23","","","3","","1","","","","","215302","false","","","" "1206485","Keller, Lukas (Goethe Univ, Germany);Al Mamoori, Mohanad K. I. (Goethe Univ, Germany);Pieper, Jonathan (Goethe Univ, Germany);Gspan, Christian (Graz Ctr Electron Microscopy, Austria);Stockem, Irina [irist97] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Schroeder, Christian (Bielefeld Univ Appl Sci, Germany);Barth, Sven (Vienna Univ Technol, Austria);Winkler, Robert (Graz Centre for Electron Microscopy, Graz, Austria);Plank, Harald (Graz Univ Technol, Austria);Pohlit, Merlin (Goethe Univ, Germany);Mueller, Jens (Goethe Univ, Germany);Huth, Michael (Goethe Univ, Germany)","Direct-write of free-form building blocks for artificial magnetic 3D lattices","Artikel i tidskrift","Refereegranskat","eng","Scientific Reports","2045-2322","2045-2322","published","8","","","","","2018","","","","NATURE PUBLISHING GROUP","","","","","","","10.1038/s41598-018-24431-x","000430280600012","29670129","","urn:nbn:se:liu:diva-147798","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Deutsche Forschungsgemeinschaft (DFG) [SFB/TR 49]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]; Faculty of Materials Engineering, University of Babylon, Babylon, Iraq; Deutscher Akademischer Austauschdienst (DAAD); COST Action [CM1301]</p>","<p>By the fabrication of periodically arranged nanomagnetic systems it is possible to engineer novel physical properties by realizing artificial lattice geometries that are not accessible via natural crystallization or chemical synthesis. This has been accomplished with great success in two dimensions in the fields of artificial spin ice and magnetic logic devices, to name just two. Although first proposals have been made to advance into three dimensions (3D), established nanofabrication pathways based on electron beam lithography have not been adapted to obtain free-form 3D nanostructures. Here we demonstrate the direct-write fabrication of freestanding ferromagnetic 3D nano-architectures. By employing micro-Hall sensing, we have determined the magnetic stray field generated by our free-form structures in an externally applied magnetic field and we have performed micromagnetic and macro-spin simulations to deduce the spatial magnetization profiles in the structures and analyze their switching behavior. Furthermore we show that the magnetic 3D elements can be combined with other 3D elements of different chemical composition and intrinsic material properties.</p>","","","","","","","","","","","","","2018-05-17","2018-05-17","2018-06-04","http://liu.diva-portal.org/smash/get/diva2:1206485/FULLTEXT01.pdf","","12","","1","","","","","6160","false","","","" "1213614","Tasnadi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Natl Univ Sci and Technol MISIS, Russia);Rogström, Lina [linro82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Zhu, Jianqiang [jiazh32] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Wang, Fei [feiwa67] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Hsu, Tun-Wei [tunhs26] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Lind, Hans [hanli61] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Natl Univ Sci and Technol MISIS, Russia);Johansson, Mats [matjo02] [0000-0003-4577-0976] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (SECO Tools AB, Sweden);Odén, Magnus [magod41] [0000-0002-2286-5588] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska fakulteten [872902])","High temperature thermodynamics of spinodal decomposition in arc deposited TixNbyAlzN coatings","Artikel i tidskrift","Refereegranskat","eng","Materials & design","0264-1275","1873-4197","published","150","","","165","170","2018","","","","Elsevier","","","","","","","10.1016/j.matdes.2018.04.033","000432565300019","","2-s2.0-85045795846","urn:nbn:se:liu:diva-148238","","","Hard coating films; NbN; Cathodic arc deposition; Thermodynamic stability; Hardness","Metallurgi och metalliska material (20506)","","","<p>Funding Agencies|VINN Excellence Center Functional Nanoscale Materials (FunMat-II) [201605156]; Swedish Research Council (VR) [201504391]; Swedish Foundation for Strategic Research (SSF) program [621-2012-4401]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; Vinnova [201302355]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005, K2-2017-080, 211]</p>","<p data-select-like-a-boss=""1"">Using first principles calculations and experimental methods we show that B1 structured solid solution TixNbyAlzN can be grown. The mixing free energy surface indicates that the alloys should decompose. Theoretical analysis of the thermodynamic driving force towards the spinodal decomposition shows that the force can be different in alloys with equally low thermodynamic stability but different Nb content, indicating that the detailed picture of the decomposition should also be different. Electron microscopy and nanoindentation underlines different age hardening of the samples. We demonstrate that an alloy with the optimized composition, Ti0.42Nb0.17Al0.41N combines high thermal stability and age hardening behavior.</p>","","","","","","","","","","","","","2018-06-05","2018-06-05","2018-06-12","","","9","","1","","","","","","true","","","" "1211310","Ekeroth, Sebastian [sebek07] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Plasma och beläggningsfysik [2225]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Münger, Peter [petmu26] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Boyd, Robert [robbo87] [0000-0002-6602-7981] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Plasma och beläggningsfysik [2225]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Ekspong, Joakim (Umeå Univ, Sweden);Wågberg, Thomas (Umeå Univ, Sweden);Edman, Ludvig (Umeå Univ, Sweden);Brenning, Nils [nilbr83] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Plasma och beläggningsfysik [2225]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (KTH Royal Inst Technol, Sweden);Helmersson, Ulf [Helmersson] [0000-0002-1744-7322] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Plasma och beläggningsfysik [2225]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Catalytic Nanotruss Structures Realized by Magnetic Self-Assembly in Pulsed Plasma","Artikel i tidskrift","Refereegranskat","eng","Nano letters (Print)","1530-6984","1530-6992","published","18","5","","3132","3137","2018","","","","American Chemical Society (ACS)","","","","","","","10.1021/acs.nanolett.8b00718","000432093200055","29624405","","urn:nbn:se:liu:diva-148107","","","Nanotrusses; nanowires; nanoparticles; iron; electrocatalysis; pulsed sputtering","Materialkemi (10403)","","","","<p>Tunable nanostructures that feature a high surface area are firmly attached to a conducting substrate and can be fabricated efficiently over significant areas, which are of interest for a wide variety of applications in, for instance, energy storage and catalysis. We present a novel approach to fabricate Fe nanoparticles using a pulsed-plasma process and their subsequent guidance and self-organization into well-defined nanostructures on a substrate of choice by the use of an external magnetic field. A systematic analysis and study of the growth procedure demonstrate that nondesired nanoparticle agglomeration in the plasma phase is hindered by electrostatic repulsion, that a polydisperse nanoparticle distribution is a consequence of the magnetic collection, and that the formation of highly networked nanotruss structures is a direct result of the polydisperse nanoparticle distribution. The nanoparticles in the nanotruss are strongly connected, and their outer surfaces are covered with a 2 nm layer of iron oxide. A 10 mu m thick nanotruss structure was grown on a lightweight, flexible and conducting carbon-paper substrate, which enabled the efficient production of H-2 gas from water splitting at a low overpotential of 210 mV and at a current density of 10 mA/cm(2).</p>","","","","","","","","","","","","","2018-05-30","2018-05-30","2018-06-12","","Knut och Alice Wallenbergs Stiftelse [KAW 14.0276]","8","","2","","","","","","false","","","" "1209622","Berggren, Karl-Fredrik [karbe79] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Tellander, Felix (Lund Univ, Sweden);Yakymenko, Iryna [iryya88] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Basic modelling of transport in 2D wave-mechanical nanodots and billiards with balanced gain and loss mediated by complex potentials","Artikel i tidskrift","Refereegranskat","eng","Journal of Physics: Condensed Matter","0953-8984","1361-648X","published","30","20","","","","2018","","","","IOP PUBLISHING LTD","","","","","","","10.1088/1361-648X/aabbfc","000431067600001","29620539","","urn:nbn:se:liu:diva-147905","","","open quantum dots; transport; non-Hermitian quantum mechanics; parity-time symmetry; symmetry breaking; exceptional points; musical instruments","Annan fysik (10399)","","","","<p>Non-Hermitian quantum mechanics with parity-time (PT) symmetry is presently gaining great interest, especially within the fields of photonics and optics. Here, we give a brief overview of low-dimensional semiconductor nanodevices using the example of a quantum dot with input and output leads, which are mimicked by imaginary potentials for gain and loss, and how wave functions, particle flow, coalescence of levels and associated breaking of PT symmetry may be analysed within such a framework. Special attention is given to the presence of exceptional points and symmetry breaking. Related features for musical string instruments and wolf-notes are outlined briefly with suggestions for further experiments.</p>","","","","","","","","","","","","","2018-05-23","2018-05-23","2018-06-13","","","3","","1","","","","","204003","false","","","" "1213611","Sangiovanni, Davide [davsa82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Ruhr Univ Bochum, Germany)","Inherent toughness and fracture mechanisms of refractory transition-metal nitrides via density-functional molecular dynamics","Artikel i tidskrift","Refereegranskat","eng","Acta Materialia","1359-6454","1873-2453","published","151","","","11","20","2018","","","","PERGAMON-ELSEVIER SCIENCE LTD","","","","","","","10.1016/j.actamat.2018.03.038","000432760300002","","","urn:nbn:se:liu:diva-148240","","","Refractory transition-metal nitrides; Ab initio molecular dynamics; Toughness; Fracture; Electronic structures","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Olle Engkvist Foundation</p>","<p>Hard refractory transition-metal nitrides possess unique combinations of outstanding mechanical and physical properties, but are typically brittle. Recent experimental results demonstrated that single-crystal NaCI-structure (B1) V0.5Mo0.5N pseudobinary solid solutions are both hard (similar to 20 GPa) and ductile; that is, they exhibit toughness, which is unusual for ceramics. However, key atomic-scale mechanisms underlying this inherent toughness are unknown. Here, I carry out density-functional ab initio molecular dynamics (AIMD) simulations at room temperature to identify atomistic processes and associated changes in the electronic structure which control strength, plasticity, and fracture in V0.5Mo0.5N, as well as reference B1 TiN, subject to amp;lt;001amp;gt; and amp;lt;110amp;gt; tensile deformation. AIMD simulations reveal that V0.5Mo0.5N is considerably tougher than TiN owing to its ability to (i) isotropically redistribute mechanical stresses within the elastic regime, (ii) dissipate the accumulated strain energy by activating local structural transformations beyond the yield point. In direct contrast, TiN breaks in brittle manner when applied stresses reach its tensile strength. Charge transfer maps show that the adaptive mechanical response of V0.5Mo0.5N originates from highly populated d-d metallic-states, which allow for counterbalancing the destabilization induced via tensile deformation by enabling formation of new chemical bonds. The high ionic character and electron-localization in TiN precludes the possibility of modifying bonding geometries to accommodate the accumulated stresses, thus suddenly causing materials fracture for relatively low strain values. </p>","","","","","","","","","","","","","2018-06-05","2018-06-05","2018-06-13","","","1","","2","","","","","","false","","","" "1218959","Li, Qing (Soochow Univ, Peoples R China);Yang, Biao (Soochow Univ, Peoples R China);Björk, Jonas [jonbj66] [0000-0002-1345-0006] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Zhong, Qigang (Soochow Univ, Peoples R China; Justus Liebig Univ Giessen, Germany);Ju, Huanxin (Univ Sci and Technol China, Peoples R China);Zhang, Junjie (Soochow Univ, Peoples R China);Cao, Nan (Soochow Univ, Peoples R China);Shi, Ziliang (Soochow Univ, Peoples R China);Zhang, Haiming (Soochow Univ, Peoples R China);Ebeling, Daniel (Justus Liebig Univ Giessen, Germany);Schirmeisen, Andre (Justus Liebig Univ Giessen, Germany);Zhu, Junfa (Univ Sci and Technol China, Peoples R China);Chi, Lifeng (Soochow Univ, Peoples R China)","Hierarchical Dehydrogenation Reactions on a Copper Surface","Artikel i tidskrift","Refereegranskat","eng","Journal of the American Chemical Society","0002-7863","1520-5126","published","140","19","","6076","6082","2018","","","","AMER CHEMICAL SOC","","","","","","","10.1021/jacs.7b12278","000432753400009","29543446","","urn:nbn:se:liu:diva-148386","","","","Oorganisk kemi (10404)","","","<p>Funding Agencies|National Science Foundation of China [21661132006, 21790053, 21622306, 91545127, 21473178, 21773222]; National Major State Basic Research Development Program of China [2017YFA0205002, 2014CB932600]; Natural Science Foundation of Jiangsu Province [BK20140305, BK20130285]</p>","<p>Hierarchical control of chemical reactions is being considered as one of the most ambitious and challenging topics in modern organic chemistry. In this study, we have realized the one-by-one scission of the X-H bonds (X = N and C) of aromatic amines in a controlled fashion on the Cu(lll) surface. Each dehydrogenation reaction leads to certain metal-organic supramolecular structures, which were monitored in single-bond resolution via scanning tunneling microscopy and noncontact atomic force microscopy. Moreover, the reaction pathways were elucidated from X-ray photoelectron spectroscopy measurements and density functional theory calculations. Our insights pave the way for connecting molecules into complex structures in a more reliable and predictable manner, utilizing carefully tuned stepwise on-surface synthesis protocols.</p>","","","","","","","","","","","","","2018-06-15","2018-06-15","2018-06-15","","","13","","2","","","","","","false","","","" "1217881","Sangiovanni, Davide Giuseppe [davsa82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Copper adatom, admolecule transport, and island nucleation on TiN(0 0 1) via <em>ab initio</em> molecular dynamics","Artikel i tidskrift","Refereegranskat","eng","Applied Surface Science","0169-4332","1873-5584","published","50","","","180","189","2018","","","","Elsevier","","","","","","","10.1016/j.apsusc.2018.04.191","000433199000021","","","urn:nbn:se:liu:diva-148576","","","","Kemi (104);Den kondenserade materiens fysik (10304)","","","<p>Funding agencies: Olle Engkvist Foundation</p>","<p>Density-functional <em>ab initio</em> molecular dynamics (AIMD) simulations are carried out to determine Cu adatom and admolecule transport properties as a function of temperature, as well as atomistic processes leading to formation of Cu/TiN(0 0 1) islands at 350 K. At very low temperatures <em>T</em> ≤ 200 K, Cu adatoms (Cuad) migrate among favored fourfold-hollow surface sites by passing across atop-Ti metastable positions. For increasing temperatures, however, Cuad transport becomes progressively more isotropic, and switches continuously from normal- to super-diffusive with mean-square displacement dependencies on time that alternate between linear and exponential. Despite that, the Cuad diffusivity <em>D</em> can be expressed by a fairly Arrhenius-like behavior <em>D</em>(<em>T</em>) = 8.26(×2±1) × 10−4 cm2 s−1exp[(−0.04 ± 0.01 eV)/(<em>k</em>B<em>T</em>)] over the entire investigated temperature range (100 ≤ <em>T</em> ≤ 1000 K). AIMD simulations also reveal that the condensation of Cu adatoms into Cux&gt;1 adspecies is kinetically hindered by long-range (&gt;5.5 Å) adatom/adatom repulsion. During Cu island nucleation, all Cu atoms occupy atop-N positions indicating favored Cu(0 0 1)/TiN(0 0 1) epitaxial growth. Nevertheless, Cu agglomerates formed by five, or more, atoms tend to arrange in 3D structures, which maximize intracluster bonds while minimizing film/substrate interactions. Results here presented provide insights for understanding the properties of weakly-interacting metal/substrate interface systems in general.</p>","","","","","","","","","","","","","2018-06-13","2018-06-13","2018-06-18","","","1","","1","","","","","","false","","","" "1209583","Eriksson, Peter [peter35] [0000-0002-1192-1492] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Molekylär ytfysik och nanovetenskap [9601]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Tal, Alexey [aleta94] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Skallberg, Andreas [andsk54] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Molekylär ytfysik och nanovetenskap [9601]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Brommesson, Caroline [carsk36] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Molekylär ytfysik och nanovetenskap [9601]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Hu, Zhang-Jun [zhahu14] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Molekylär ytfysik och nanovetenskap [9601]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Boyd, Robert [robbo87] [0000-0002-6602-7981] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Plasma och beläggningsfysik [2225]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Olovsson, Weine [weiol14] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Fairley, Neal (Casa Software Ltd, Bay House, Teignmouth, United Kingdom);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Materials Modeling and Development Laboratory, National University of Science and Technology “MISIS”, Moscow, Russia);Zhang, Xuanjun (Faculty of Health Sciences, University of Macau, Macau, SAR, China);Uvdal, Kajsa [kajuv09] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Molekylär ytfysik och nanovetenskap [9601]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Cerium oxide nanoparticles with antioxidant capabilities and gadolinium integration for MRI contrast enhancement","Artikel i tidskrift","Refereegranskat","eng","Scientific Reports","2045-2322","2045-2322","published","8","","","","","2018","","","","Nature Publishing Group","","","","","","","10.1038/s41598-018-25390-z","000431293100003","29725117","2-s2.0-85046679522","urn:nbn:se:liu:diva-147910","","","","Annan fysik (10399)","","","<p>Funding Agencies|Swedish Research Council [621-2013-5357]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; Knut and Alice Wallenberg Foundation [2012.0083 CTS 15:507]; Centre in Nano Science and Nano technology at LiTH (CeNano) at Linkoping University; CoTXS; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005, K2-2017-080, 211]</p>","<p>The chelating gadolinium-complex is routinely used as magnetic resonance imaging (MRI) -contrast enhancer. However, several safety issues have recently been reported by FDA and PRAC. There is an urgent need for the next generation of safer MRI-contrast enhancers, with improved local contrast and targeting capabilities. Cerium oxide nanoparticles (CeNPs) are designed with fractions of up to 50% gadolinium to utilize the superior MRI-contrast properties of gadolinium. CeNPs are well-tolerated in vivo and have redox properties making them suitable for biomedical applications, for example scavenging purposes on the tissue-and cellular level and during tumor treatment to reduce in vivo inflammatory processes. Our near edge X-ray absorption fine structure (NEXAFS) studies show that implementation of gadolinium changes the initial co-existence of oxidation states Ce3+ and Ce4+ of cerium, thereby affecting the scavenging properties of the nanoparticles. Based on ab initio electronic structure calculations, we describe the most prominent spectral features for the respective oxidation states. The as-prepared gadolinium-implemented CeNPs are 3-5 nm in size, have r(1)-relaxivities between 7-13 mM(-1) s(-1) and show clear antioxidative properties, all of which means they are promising theranostic agents for use in future biomedical applications.</p>","","","","","","","","","","","","","2018-05-23","2018-05-23","2018-06-19","http://liu.diva-portal.org/smash/get/diva2:1209583/FULLTEXT01.pdf","","11","","1","","","","","6999","true","true","","" "1209556","Ribeiro, Luiz Antonio [luiri41] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Monteiro, Fabio Ferreira (Univ Brasilia, Brazil);da Cunha, Wiliam Ferreira (Univ Florida, FL 32611 USA);Magela e Silva, Geraldo (Univ Brasilia, Brazil)","Charge Carrier Scattering in Polymers: A New Neutral Coupled Soliton Channel","Artikel i tidskrift","Refereegranskat","eng","Scientific Reports","2045-2322","2045-2322","published","8","","","","","2018","","","","NATURE PUBLISHING GROUP","","","","","","","10.1038/s41598-018-24948-1","000430919900044","29700347","","urn:nbn:se:liu:diva-147925","","","","Annan fysik (10399)","","","<p>Funding Agencies|Brazilian Research Council CNPq; Brazilian Research Council CAPES; Brazilian Research Council FINATEC; Brazilian Research Council FAPDF grant [0193.000942/2015]; Brazilian Ministry of Planning, Budget and Management [DIPLA 005/2016]</p>","<p>The dynamical scattering of two oppositely charged bipolarons in non-degenerate organic semiconducting lattices is numerically investigated in the framework of a one-dimensional tight-biding-Hubbard model that includes lattice relaxation. Our findings show that it is possible for the bipolaron pair to merge into a state composed of a confined soliton-antisoliton pair, which is characterized by the appearance of states within less than 0.1 eV from the Fermi level. This compound is in a narrow analogy to a meson confining a quark-antiquark pair. Interestingly, solitons are quasi-particles theoretically predicted to arise only in polymer lattices with degenerate ground state: in the general case of nondegenerate ground state polymers, isolated solitons are not allowed.</p>","","","","","","","","","","","","","2018-05-23","2018-05-23","2018-06-19","http://liu.diva-portal.org/smash/get/diva2:1209556/FULLTEXT01.pdf","","4","","1","","","","","6595","false","","","" "1205882","Silverå Ejneby, Malin [malsi14] (Linköpings universitet [276], Institutionen för klinisk och experimentell medicin [322], Avdelning för neurobiologi [877701]) (Linköpings universitet [276], Medicinska fakulteten [872900]);Wu, Xiongyu [xiowu62] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Kemi [9600]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Ottosson, Nina [ninot92] (Linköpings universitet [276], Institutionen för klinisk och experimentell medicin [322], Avdelning för neurobiologi [877701]) (Linköpings universitet [276], Medicinska fakulteten [872900]);Münger, E Peter [petmu26] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Lundström, Ingemar [inglu57] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Sensor- och aktuatorsystem [878650]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Konradsson, Peter [petko14] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Kemi [9600]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Elinder, Fredrik [freel71] [0000-0001-9125-5583] (Linköpings universitet [276], Institutionen för klinisk och experimentell medicin [322], Avdelning för neurobiologi [877701]) (Linköpings universitet [276], Medicinska fakulteten [872900])","Atom-by-atom tuning of the electrostatic potassium-channel modulator dehydroabietic acid","Artikel i tidskrift","Refereegranskat","eng","The Journal of General Physiology","0022-1295","1540-7748","published","150","5","","731","750","2018","","","New York, United States","Rockefeller Institute for Medical Research","","","","","","","10.1085/jgp.201711965","000434417800008","","2-s2.0-85046705149","urn:nbn:se:liu:diva-147837","","","","Fysiologi (30106)","","","<p>Funding agencies: Swedish Research Council [2016-02615]; Swedish Heart-Lung Foundation [20150672]; Swedish Brain Foundation [2016-0326]</p>","<p data-select-like-a-boss=""1"">Dehydroabietic acid (DHAA) is a naturally occurring component of pine resin that was recently shown to open voltage-gated potassium (KV) channels. The hydrophobic part of DHAA anchors the compound near the channel’s positively charged voltage sensor in a pocket between the channel and the lipid membrane. The negatively charged carboxyl group exerts an electrostatic effect on the channel’s voltage sensor, leading to the channel opening. In this study, we show that the channel-opening effect increases as the length of the carboxyl-group stalk is extended until a critical length of three atoms is reached. Longer stalks render the compounds noneffective. This critical distance is consistent with a simple electrostatic model in which the charge location depends on the stalk length. By combining an effective anchor with the optimal stalk length, we create a compound that opens the human KV7.2/7.3 (M type) potassium channel at a concentration of 1 µM. These results suggest that a stalk between the anchor and the effector group is a powerful way of increasing the potency of a channel-opening drug.</p>","","","","","","","","","","","","","2018-05-15","2018-05-15","2018-06-28","http://liu.diva-portal.org/smash/get/diva2:1205882/FULLTEXT01.pdf","","7","","2","urn:nbn:se:liu:diva-147838","","","","","true","","","" "1236445","Garhammer, Julian (Univ Bayreuth, Germany);Hofmann, Fabian (Univ Bayreuth, Germany);Armiento, Rickard [ricar47] [0000-0002-5571-0814] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Kuemmel, Stephan (Univ Bayreuth, Germany)","On the challenge to improve the density response with unusual gradient approximations","Artikel i tidskrift","Refereegranskat","eng","European Physical Journal B: Condensed Matter Physics","1434-6028","1434-6036","published","91","7","","","","2018","","","","SPRINGER","","","","","","","10.1140/epjb/e2018-90119-4","000437971200005","","","urn:nbn:se:liu:diva-149853","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Deutsche Forschungsgemeinschaft [Graduiertenkolleg 1640]; study program ""Biological Physics"" of the Elite Network of Bavaria; German-Israeli Foundation for Scientific Research and Development; University of Bayreuth Graduate School; Swedish Research Council (VR) project [2016-04810]; Swedish e-Science Research Centre (SeRC)</p>","<p>Certain excitations, especially ones of long-range charge transfer character, are poorly described by time-dependent density functional theory (TDDFT) when typical (semi-)local functionals are used. A proper description of these excitations would require an exchange-correlation response differing substantially from the usual (semi-) local one. It has recently been shown that functionals of the generalized gradient approximation (GGA) type can yield unusual potentials, mimicking features of the exact exchange derivative discontinuity and showing divergences on orbital nodal surfaces. We here investigate whether these unusual potential properties translate into beneficial response properties. Using the Sternheimer formalism we closely investigate the response obtained with the 2013 exchange approximation by Armiento and Kummel (AK13) and the 1988 exchange approximation by Becke (B88), both of which show divergences on orbital nodal planes. Numerical calculations for Na-2 as well as analytical and numerical calculations for the hydrogen atom show that the response of AK13 behaves qualitatively different from usual semi-local functionals. However, the AK13 functional leads to fundamental instabilities in the asymptotic region that prevent its practical application in TDDFT. Our findings may help the development of future improved functionals. They also corroborate that the frequency-dependent Sternheimer formalism is excellently suited for running and analyzing TDDFT calculations.</p>","","","","","","","","","","","","","2018-08-02","2018-08-02","2018-08-02","","","4","","1","","","","","159","false","","","" "1229737","Ponomareva, A. V. (Natl Univ Sci and Technol MISIS, Russia);Ruban, A. V. (KTH Royal Inst Technol, Sweden; Leoben Forsch GmbH, Austria);Mukhamedov, B. O. (Natl Univ Sci and Technol MISIS, Russia);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Effect of multicomponent alloying with Ni, Mn and Mo on phase stability of bcc Fe-Cr alloys","Artikel i tidskrift","Refereegranskat","eng","Acta Materialia","1359-6454","1873-2453","published","150","","","117","129","2018","","","","PERGAMON-ELSEVIER SCIENCE LTD","","","","","","","10.1016/j.actamat.2018.02.007","000433272400011","","","urn:nbn:se:liu:diva-149377","","","First-principles calculations; Fe-Cr system; Multicomponent alloying; Phase stability; Spinodal decompositon; Mixing enthalpy","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Research Council [2015-04391]; Swedish Government Strategic Research Areas in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; Swedish e-science Research Centre (SeRC); Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of NUST ""MISIS"" [K2-2017-080]; Swedish Research Council (VR project) [2015-05538]; European Research Council; VINNEX center Hero-m - Swedish Governmental; Agency for Innovation Systems (VINNOVA); Swedish industry; Royal Institute of Technology (KTH); Austrian Federal Government (Bundesministerium fur Verkehr, Innovation und Technologie); Austrian Federal Government (Bundesministerium fur Wirtschaft, Familie und Jugend)</p>","<p>Fe-Cr system attracts lot of attention in condensed matter physics due to its technological importance and extraordinary physics related to a non-trivial interplay between magnetic and chemical interactions. However, the effect of multicomponent alloying on the properties of Fe-Cr alloys are less studied. We have calculated the mixing enthalpy, magnetic moments, effective chemical, strain-induced and magnetic exchange interactions to investigate the alloying effect of Ni, Mn, Mo on the phase stability of the ferromagnetic bcc Fe Cr system at zero K. We demonstrate that the alloying reduces the stability of Fe-Cr alloys and expands the region of spinodal decomposition. At the same time, the mixing enthalpy in ternary Fe100-c-05CrcNi05 alloys indicates a stability of solid solution phase up to 6 at. % Cr. In Fem(100-c-07)CrNi(05)Mn(01)Mo(01) alloys, we did not find any alloy composition that has negative enthalpy of formation. Analyzing magnetic and electronic properties of the alloys and investigating magnetic, chemical and strain-induced interactions in the studied systems, we provide physically transparent picture of the main factors leading to the destabilization of the Fe-Cr solid solutions by the multicomponent alloying with Ni, Mn, Mo. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.</p>","","","","","","","","","","","","","2018-07-02","2018-07-02","2018-08-03","","","4","","2","","","","","","false","","","" "1234387","Burakovsky, Leonid (Los Alamos Natl Lab, NM 87545 USA);Burakovsky, Naftali (Los Alamos Natl Lab, NM 87545 USA);Preston, Dean (Los Alamos Natl Lab, NM 87545 USA);Simak, Sergei I [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Systematics of the Third Row Transition Metal Melting: The HCP Metals Rhenium and Osmium","Artikel i tidskrift","Refereegranskat","eng","Crystals","2073-4352","","published","8","6","","","","2018","","","","MDPI","","","","","","","10.3390/cryst8060243","000436129400012","","","urn:nbn:se:liu:diva-149722","","","quantum molecular dynamics; phase diagram; melting curve; transition metal","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|US DOE/NNSA</p>","<p>The melting curves of rhenium and osmium to megabar pressures are obtained from an extensive suite of ab initio quantum molecular dynamics (QMD) simulations using the Z method. In addition, for Re, we combine QMD simulations with total free energy calculations to obtain its phase diagram. Our results indicate that Re, which generally assumes a hexagonal close-packed (hcp) structure, melts from a face-centered cubic (fcc) structure in the pressure range 20-240 GPa. We conclude that the recent DAC data on Re to 50 GPa in fact encompass both the true melting curve and the low-slope hcp-fcc phase boundary above a triple point at (20 GPa, 4240 K). A linear fit to the Re diamond anvil cell (DAC) data then results in a slope that is 2.3 times smaller than that of the actual melting curve. The phase diagram of Re is topologically equivalent to that of Pt calculated by us earlier on. Regularities in the melting curves of Re, Os, and five other 3rd-row transition metals (Ta, W, Ir, Pt, Au) form the 3rd-row transition metal melting systematics. We demonstrate how this systematics can be used to estimate the currently unknown melting curve of the eighth 3rd-row transition metal Hf.</p>","","","","","","","","","","","","","2018-07-24","2018-07-24","2018-08-14","http://liu.diva-portal.org/smash/get/diva2:1234387/FULLTEXT01.pdf","","4","","0","","","","","243","false","true","","" "1235312","Ektarawong, Annop [annek02] [0000-0002-6059-6833] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Max Planck Inst Eisenforsch GmbH, Germany)","Stability of SnSe_1-xS_x solid solutions revealed by first-principles cluster expansion","Artikel i tidskrift","Refereegranskat","eng","Journal of Physics: Condensed Matter","0953-8984","1361-648X","published","30","29","","","","2018","","","","IOP PUBLISHING LTD","","","","","","","10.1088/1361-648X/aacb9c","000436395200001","29889052","","urn:nbn:se:liu:diva-149681","","","configurational thermodynamics; first-principles approach; cluster-expansion formalism; SnSe1-xSx alloy","Fysikalisk kemi (10402)","","","<p>Funding Agencies|Swedish Research Council (VR) [2014-6336]; Marie Sklodowska Curie Actions, Cofund [INCA 600398]; Swedish Foundation for Strategic Research (SSF); Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]</p>","<p>The configurational thermodynamics of a pseudo-binary alloy SnSe1-xSx in the Pnma phase is studied using first-principles cluster-expansion method in combination with canonical Monte Carlo simulations. We find that, despite the alloy having a tendency toward a phase decomposition into SnSe and SnS at 0 K, the two constituent binaries readily mix with each other to form random SnSe1-xSx solid solutions even at a temperature below room temperature. The obtained isostructural phase diagram of SnSe1-xSx reveals that the alloy is thermodynamically stable as a single-phase random solid solution over a whole composition range above 200 K. These findings provide a fundamental understanding on the alloying behavior of SnSe1-xSx and bring clarity to the debated clustering tendency in this alloy system.</p>","","","","","","","","","","","","","2018-07-25","2018-07-25","2018-08-14","http://liu.diva-portal.org/smash/get/diva2:1235312/FULLTEXT01.pdf","","2","","1","","","","","29LT01","false","true","","" "1234401","Silva, Gesiel Gomes (Goias Fed Inst Educ Sci and Technol, Brazil; Univ Brasilia, Brazil);da Cunha, Wiliam Ferreira (Univ Brasilia, Brazil);de Sousa Junior, Rafael Timoteo (Univ Brasilia, Brazil);Almeida Fonseca, Antonio Luciano (Univ Brasilia, Brazil);Ribeiro, Luiz Antonio [luiri41] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Univ Brasilia, Brazil);Magela e Silva, Geraldo (Univ Brasilia, Brazil)","Influence of quasi-particle density over polaron mobility in armchair graphene nanoribbons","Artikel i tidskrift","Refereegranskat","eng","Physical Chemistry, Chemical Physics - PCCP","1463-9076","1463-9084","published","20","24","","16712","16718","2018","","","","ROYAL SOC CHEMISTRY","","","","","","","10.1039/c8cp02373e","000436032900042","29878013","","urn:nbn:se:liu:diva-149710","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|CNPq; CAPES; FAP-DF; CENAPAD-SP; Brazilian Ministry of Planning, Development and Management [005/2016, 11/2016]; DPGU - Brazilian Union Public Defender [066/2016]; FAP-DF [0193.000.942/2015, 193.001.511/2017]</p>","<p>An important aspect concerning the performance of armchair graphene nanoribbons (AGNRs) as materials for conceiving electronic devices is related to the mobility of charge carriers in these systems. When several polarons are considered in the system, a quasi-particle wave function can be affected by that of its neighbor provided the two are close enough. As the overlap may affect the transport of the carrier, the question concerning how the density of polarons affect its mobility arises. In this work, we investigate such dependence for semiconducting AGNRs in the scope of nonadiabatic molecular dynamics. Our results unambiguously show an impact of the density on both the stability and average velocity of the quasi-particles. We have found a phase transition between regimes where increasing density stops inhibiting and starts promoting mobility; densities higher than 7 polarons per 45 angstrom present increasing mean velocity with increasing density. We have also established three different regions relating electric field and average velocity. For the lowest electric field regime, surpassing the aforementioned threshold results in overcoming the 0.3 angstrom fs(-1) limit, thus representing a transition between subsonic and supersonic regimes. For the highest of the electric fields, density effects alone are responsible for a stunning difference of 1.5 angstrom fs(-1) in the mean carrier velocity.</p>","","","","","","","","","","","","","2018-07-24","2018-07-24","2018-08-14","http://liu.diva-portal.org/smash/get/diva2:1234401/FULLTEXT01.pdf","","6","","2","","","","","","false","true","","" "1234393","Sagun, V. V. (Natl Acad Sci Ukraine, Ukraine; Univ Lisbon, Portugal);Bugaev, K. A. (Natl Acad Sci Ukraine, Ukraine);Ivanytskyi, A. I. (Natl Acad Sci Ukraine, Ukraine);Yakymenko, Ivan (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Nikonov, E. G. (JINR, Russia);Taranenko, A. V. (Natl Res Nucl Univ MEPhI Moscow Engn Phys Inst, Russia);Greiner, C. (Goethe Univ, Germany);Blaschke, D. B. (Natl Res Nucl Univ MEPhI Moscow Engn Phys Inst, Russia; Univ Wroclaw, Poland; JINR Dubna, Russia);Zinovjev, G. M. (Natl Acad Sci Ukraine, Ukraine)","Hadron resonance gas model with induced surface tension","Artikel i tidskrift","Refereegranskat","eng","European Physical Journal A","1434-6001","1434-601X","published","54","6","","","","2018","","","","SPRINGER","","","","","","","10.1140/epja/i2018-12535-1","000436363800001","","","urn:nbn:se:liu:diva-149716","","","","Astronomi, astrofysik och kosmologi (10305)","","","<p>Funding Agencies|Section of Nuclear Physics of National Academy of Sciences of Ukraine; Fundacao pars a Ciencia e Tecnologia (FCT), Portugal; instituto Superior Tocnico, Universidade de Lisboa [UID/FIS/00099/2013]; Ministry of Science and Education of the Russian Federation [3.3380.2017/4.6]; National Research Nuclear University ""MEPhl"" in the framework of the Russian Academic Excellence Project [02.a03.21.0005]; HIC; MENAI Academic Excellence program [02.a03.21.0005]</p>","<p>Here we present a generalization of the multicomponent Van der Waals equation of state in the grand canonical ensemble. For the one-component case the third and fourth virial coefficients are calculated analytically. It is shown that the adjustment of a single model parameter allows us to reproduce the third and fourth virial coefficients of the gas of hard spheres with small deviations from their exact values. A thorough comparison of the compressibility factor and speed of sound of this model with the one- and two-component Carnahan-Starling equation of state is made. We show that the model with the induced surface tension can reproduce the results of the Carnahan-Starling equation of state up to the packing fractions 0.2-0.22 at which the Van der Waals equation of state is inapplicable. Using this approach we develop an entirely new hadron resonance gas model and apply it to a description of the hadron yield ratios measured at AGS, SPS, RHIC and ALICE energies of nuclear collisions. We confirm that the strangeness enhancement factor has a peak at low AGS energies and that there is a jump of chemical freeze-out temperature between the two highest AGS energies. Also we argue that the chemical equilibrium of strangeness, i.e gamma(s) similar or equal to 1, observed above the center of mass collision energy 8.7 GeV, may be related to a hadronization of quark gluon bags which have a Hagedorn mass spectrum, and, hence, it may be a new signal for the onset of deconfinement.</p>","","","","","","","","","","","","","2018-07-24","2018-07-24","2018-08-14","","","9","","1","","","","","100","false","","","" "1236450","Sangiovanni, Davide Giuseppe [davsa82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Ruhr Univ Bochum, Germany);Kostov Gueorguiev, Gueorgui [guegu96] [0000-0001-9402-1491] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Kakanakova-Georgieva, Anelia [aneka59] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Ab initio molecular dynamics of atomic-scale surface reactions: insights into metal organic chemical vapor deposition of AlN on graphene","Artikel i tidskrift","Refereegranskat","eng","Physical Chemistry, Chemical Physics - PCCP","1463-9076","1463-9084","published","20","26","","17751","17761","2018","","","","Royal Society of Chemistry","","","","","","","10.1039/c8cp02786b","000437473300021","29915819","","urn:nbn:se:liu:diva-149847","","","","Materialkemi (10403)","","","<p>Funding Agencies|Swedish Research Council (VR) through FLAG-ERA JTC project GRIFONE [VR 2015-06816, VR 2017-04071]; Olle Engkvist Foundation</p>","<p>Metal organic chemical vapor deposition (MOCVD) of group III nitrides on graphene heterostructures offers new opportunities for the development of flexible optoelectronic devices and for the stabilization of conceptually-new two-dimensional materials. However, the MOCVD of group III nitrides is regulated by an intricate interplay of gas-phase and surface reactions that are beyond the resolution of experimental techniques. We use density-functional ab initio molecular dynamics (AIMD) with van der Waals corrections to identify atomistic pathways and associated electronic mechanisms driving precursor/surface reactions during metal organic vapor phase epitaxy at elevated temperatures of aluminum nitride on graphene, considered here as model case study. The results presented provide plausible interpretations of atomistic and electronic processes responsible for delivery of Al, C adatoms, and C-Al, CHx, AlNH2 admolecules on pristine graphene via precursor/surface reactions. In addition, the simulations reveal C adatom permeation across defect-free graphene, as well as exchange of C monomers with graphene carbon atoms, for which we obtain rates of approximate to 0.3 THz at typical experimental temperatures (1500 K), and extract activation energies Eexca = 0.28 +/- 0.13 eV and attempt frequencies A(exc) = 2.1 (x1.7(+/- 1)) THz via Arrhenius linear regression. The results demonstrate that AIMD simulations enable understanding complex precursor/surface reaction mechanisms, and thus propose AIMD to become an indispensable routine prediction-tool toward more effective exploitation of chemical precursors and better control of MOCVD processes during synthesis of functional materials.</p>","","","","","","","","","","","","","2018-08-02","2018-08-02","2018-08-20","http://liu.diva-portal.org/smash/get/diva2:1236450/FULLTEXT01.pdf","","3","","2","","","","","","false","true","","" "1236453","Bykov, Maxim (Univ Bayreuth, Germany);Bykova, Elena (Deutsch Elektronen Synchrotron DESY, Germany);Koemets, Egor (Univ Bayreuth, Germany);Fedotenko, Timofey (Univ Bayreuth, Germany);Aprilis, Georgios (Univ Bayreuth, Germany);Glazyrin, Konstantin (Deutsch Elektronen Synchrotron DESY, Germany);Liermann, Hanns-Peter (Deutsch Elektronen Synchrotron DESY, Germany);Ponomareva, Alena V. (Natl Univ Sci and Technol MISIS, Russia);Tidholm, Johan [johti34] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Tasnadi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Abrikosov, Igor A. [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Dubrovinskaia, Natalia (Univ Bayreuth, Germany);Dubrovinsky, Leonid (Univ Bayreuth, Germany)","High-Pressure Synthesis of a Nitrogen-Rich Inclusion Compound ReN₈·xN₂ with Conjugated Polymeric Nitrogen Chains","Artikel i tidskrift","Refereegranskat","eng","Angewandte Chemie International Edition","1433-7851","1521-3773","published","57","29","","9048","9053","2018","","","","WILEY-V C H VERLAG GMBH","","","","","","","10.1002/anie.201805152","000438195200045","29774981","","urn:nbn:se:liu:diva-149844","","","high-energy-density materials; high-pressure chemistry; nitrides; polymeric nitrogen; X-ray diffraction","Oorganisk kemi (10404)","","","<p>Funding Agencies|German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) [DU 954-8/1, DU 954-11/1]; Federal Ministry of Education and Research, Germany (BMBF) [5K16WC1]; DFG [FOR2125, FOR 2440]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005, K2-2017-080]; Swedish Research Council (VR) [2015-04391]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; VINN Excellence Center Functional Nanoscale Materials (FunMat-2) Grant [2016-05156]</p>","<p>A nitrogen-rich compound, ReN(8)xN(2), was synthesized by a direct reaction between rhenium and nitrogen at high pressure and high temperature in a laser-heated diamond anvil cell. Single-crystal X-ray diffraction revealed that the crystal structure, which is based on the ReN8 framework, has rectangular-shaped channels that accommodate nitrogen molecules. Thus, despite a very high synthesis pressure, exceeding 100GPa, ReN(8)xN(2) is an inclusion compound. The amount of trapped nitrogen (x) depends on the synthesis conditions. The polydiazenediyl chains [-N=N-] that constitute the framework have not been previously observed in any compound. Abinitio calculations on ReN(8)xN(2) provide strong support for the experimental results and conclusions.</p>","","","","","","","","","","","","","2018-08-02","2018-08-02","2018-08-22","","","13","","2","","","","","","false","","","" "1218607","Ektarawong, Annop [annek02] [0000-0002-6059-6833] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Thermodynamic consideration and ground-state search of icosahedral boron subselenide B-12(B1-xSex)(2) from a first-principles cluster expansion","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","97","17","","","","2018","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.97.174103","000432960900001","","","urn:nbn:se:liu:diva-148388","","","","Annan fysik (10399)","","","<p>Funding Agencies|Swedish Foundation for Strategic Research (SSF) through the Future Research Leaders programme (the sixth generation)</p>","<p>The phase stability of icosahedral boron subselenide B-12(B1-xSex)(2), where 0.5 amp;lt;= x amp;lt;= 1, is explored using a first-principles cluster expansion. The results shows that, instead of a continuous solid solution, B-12(B1-xSex)(2) is thermodynamically stable as an individual line compound at the composition of B9.5Se. The ground-state configuration of B9.5Se is represented by a mixture of B-12(Se-Se), B-12(B-Se), and B-12(Se-B) with a ratio of 1: 1: 1, where they form a periodic ABCABC... stacking sequence of B-12(Se-Se), B-12(B-Se), and B-12(Se-B) layers along the c axis of the hexagonal conventional unit cell. The structural and electronic properties of the ground-state B9.5Se are also derived and discussed. By comparing the derived ground-state properties of B9.5Se to the existing experimental data of boron subselenide B similar to 13Se, I proposed that the as-synthesized boron subselenide B similar to 13Se, as reported in the literature, has the actual composition of B9.5Se.</p>","","","","","","","","","","","","","2018-06-14","2018-06-14","2018-08-29","","","1","","2","","","","","174103","false","","","" "1218964","Ektarawong, Annop [annek02] [0000-0002-6059-6833] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Max Planck Inst Eisenforsch GmbH, Germany)","Structural models of increasing complexity for icosahedral boron carbide with compositions throughout the single-phase region from first principles","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","97","17","","","","2018","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.97.174104","000433010000001","","","urn:nbn:se:liu:diva-148384","","","","Annan fysik (10399)","","","<p>Funding Agencies|Swedish Research Council (VR) [2014-6336, 2014-4750]; Marie Sklodowska Curie Actions [INCA 600398]; Swedish Foundation for Strategic Research (SSF) through the Future Research Leaders 6 program; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]</p>","<p>We perform first-principles calculations to investigate the phase stability of boron carbide, concentrating on the recently proposed alternative structural models composed not only of the regularly studied B11Cp(CBC) and B-12(CBC), but also of B-12(CBCB) and B-12(B-4). We find that a combination of the four structural motifs can result in low-energy electron precise configurations of boron carbide. Among several considered configurations within the composition range of B10.5C and B4C, we identify in addition to the regularly studied B11Cp(CBC) at the composition of B4C two low-energy configurations, resulting in a new view of the B-C convex hull. Those are [B-12(CBC)](0.67)[B-12(B-4)](0.33) and [B-12(CBC)](0.67)[B-12(CBCB)](0.33), corresponding to compositions of B10.5C and B6.67C, respectively. As a consequence, B-12(CBC) at the composition of B6.5C, previously suggested in the literature as a stable configuration of boron carbide, is no longer part of the B-C convex hull. By inspecting the electronic density of states as well as the elastic moduli, we find that the alternative models of boron carbide can provide a reasonably good description for electronic and elastic properties of the material in comparison with the experiments, highlighting the importance of considering B-12(CBCB) and B-12(B-4), together with the previously proposed B11Cp(CBC) and B-12(CBC), as the crucial ingredients for modeling boron carbide with compositions throughout the single-phase region.</p>","","","","","","","","","","","","","2018-06-15","2018-06-15","2018-08-29","","","3","","2","","","","","174104","false","","","" "1199551","Klarbring, Johan [johkl85] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Skorodumova, Natalia V. (KTH Royal Inst Technol, Sweden; Uppsala Univ, Sweden);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Finite-temperature lattice dynamics and superionic transition in ceria from first principles","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","97","10","","","","2018","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.97.104309","000427982100003","","","urn:nbn:se:liu:diva-147104","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Research Council [2014-4750, 2014-5993]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]</p>","<p>Ab initio molecular dynamics (AIMD) in combination with the temperature dependent effective potential (TDEP) method has been used to go beyond the quasiharmonic approximation and study the lattice dynamics in ceria, CeO2, at finite temperature. The results indicate that the previously proposed connection between the B-1u phonon mode turning imaginary and the transition to the superionic phase in fluorite structured materials is an artifact of the failure of the quasiharmonic approximation in describing the lattice dynamics at elevated temperatures. We instead show that, in the TDEP picture, a phonon mode coupling to the E-u mode prevents the B-1u mode from becoming imaginary. We directly observe the superionic transition at high temperatures in our AIMD simulations and find that it is initiated by the formation of oxygen Frenkel pairs (FP). These FP are found to form in a collective process involving simultaneous motion of two oxygen ions.</p>","","","","","","","","","","","","","2018-04-20","2018-04-20","2018-08-29","","","3","","2","","","","","104309","false","","","" "1239747","Bykov, M. (Univ Bayreuth, Germany);Bykova, E. (Univ Bayreuth, Germany; DESY, Germany);Aprilis, G. (Univ Bayreuth, Germany);Glazyrin, K. (DESY, Germany);Koemets, E. (Univ Bayreuth, Germany);Chuvashova, I (Univ Bayreuth, Germany; Univ Bayreuth, Germany);Kupenko, I (Univ Munster, Germany);McCammon, C. (Univ Bayreuth, Germany);Mezouar, M. (European Synchrotron Radiat Facil, France);Prakapenka, V (Univ Chicago, IL 60437 USA);Liermann, H-P (DESY, Germany);Tasnadi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Natl Univ Sci and Technol MISIS, Russia);Ponomareva, A. V (Natl Univ Sci and Technol MISIS, Russia);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Dubrovinskaia, N. (Univ Bayreuth, Germany);Dubrovinsky, L. (Univ Bayreuth, Germany)","Fe-N system at high pressure reveals a compound featuring polymeric nitrogen chains","Artikel i tidskrift","Refereegranskat","eng","Nature Communications","2041-1723","2041-1723","published","9","","","","","2018","","","","NATURE PUBLISHING GROUP","","","","","","","10.1038/s41467-018-05143-2","000438684200008","30013071","","urn:nbn:se:liu:diva-150266","","","","Materialkemi (10403)","","","<p>Funding Agencies|National Science Foundation-Earth Sciences [EAR-1634415]; Department of Energy-GeoSciences [DE-FG02-94ER14466]; DOE Office of Science [DE-AC02-06CH11357]; Deutsche Forschungsgemeinschaft (DFG) [DU 954-11/1, DU 393-10/1]; Federal Ministry of Education and Research, Germany (BMBF) [5K16WC1]; Swedish Research Council [2015-04391]; VINN Excellence Center Functional Nanoscale Materials (FunMat-2) [2016-05156]; Swedish Government Strategic Research Areas in Materials Science on Functional Materials at Linkoping University [2009-00971]; Swedish e-Science Research Centre (SeRC); Ministry of Education and Science of the Russian Federation [14.Y26.31.0005, K2-2017-080]; RFBR [16-02-00797]</p>","<p>Poly-nitrogen compounds have been considered as potential high energy density materials for a long time due to the large number of energetic N-N or N=N bonds. In most cases high nitrogen content and stability at ambient conditions are mutually exclusive, thereby making the synthesis of such materials challenging. One way to stabilize such compounds is the application of high pressure. Here, through a direct reaction between Fe and N-2 in a laser-heated diamond anvil cell, we synthesize three ironnitrogen compounds Fe3N2, FeN2 and FeN4. Their crystal structures are revealed by single-crystal synchrotron X-ray diffraction. Fe3N2, synthesized at 50 GPa, is isostructural to chromium carbide Cr3C2. FeN2 has a marcasite structure type and features covalently bonded dinitrogen units in its crystal structure. FeN4, synthesized at 106 GPa, features polymeric nitrogen chains of [N-4(2-)](n) units. Based on results of structural studies and theoretical analysis, [N-4(2-)](n) units in this compound reveal catena-poly[tetraz-1-ene-1,4-diyl] anions.</p>","","","","","","","","","","","","","2018-08-17","2018-08-17","2018-09-10","http://liu.diva-portal.org/smash/get/diva2:1239747/FULLTEXT01.pdf","","16","","2","","","","","2756","false","true","","" "1248626","Fritton, Massimo (Deutsch Museum, Germany; Tech Univ Munich, Germany);Otte, Katrin (Bavarian Acad Sci and Humanities, Germany);Björk, Jonas [jonbj66] [0000-0002-1345-0006] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Biswas, Pronay Kumar (Univ Siegen, Germany);Heckl, Wolfgang M. (Deutsch Museum, Germany; Tech Univ Munich, Germany);Schmittel, Michael (Univ Siegen, Germany);Lackinger, Markus (Deutsch Museum, Germany; Tech Univ Munich, Germany)","The influence of ortho-methyl substitution in organometallic self-assembly - a comparative study on Cu(111) vs. Ag(111)","Artikel i tidskrift","Refereegranskat","eng","Chemical Communications","1359-7345","1364-548X","published","54","70","","9745","9748","2018","","","","ROYAL SOC CHEMISTRY","","","","","","","10.1039/c8cc04854a","000442872000007","30109325","","urn:nbn:se:liu:diva-151185","","","","Oorganisk kemi (10404)","","","","<p>Metal surface-induced dehalogenation of precursors is known to initiate self-assembly of organometallic networks, where tectons are connected via carbon-metal-carbon (C-M-C) bonds. Even though reversibility of the C-M-C bonds facilitates structural equilibration, defects associated with highly bent organometallic linkages are still commonly observed. By introducing a steric hindrance to reduce the C-M-C bond angle flexibility, we find well ordered organometallic networks of an ortho-methyl substituted 1,3,5-tris(p-bromophenyl)-benzene analogue on Cu(111) after room-temperature (RT) deposition and on Ag(111) after annealing.</p>","","","","","","","","","","","","","2018-09-17","2018-09-17","2018-09-17","","","7","","1","","","","","","false","","","" "1250605","Cai, Liangliang (Tongji Univ, Peoples R China);Yu, Xin (Tongji Univ, Peoples R China);Liu, Mengxi (Natl Ctr Nanosci and Technol, Peoples R China);Sun, Qiang (Tongji Univ, Peoples R China);Bao, Meiling (Tongji Univ, Peoples R China);Zha, Zeqi (Natl Ctr Nanosci and Technol, Peoples R China; Univ Chinese Acad Sci, Peoples R China);Pan, Jinliang (Natl Ctr Nanosci and Technol, Peoples R China; Univ Chinese Acad Sci, Peoples R China);Ma, Honghong (Tongji Univ, Peoples R China);Ju, Huanxin (Univ Sci and Technol China, Peoples R China);Hu, Shanwei (Univ Sci and Technol China, Peoples R China);Xu, Liang (Tongji Univ, Peoples R China);Zou, Jiacheng (Tongji Univ, Peoples R China);Yuan, Chunxue (Tongji Univ, Peoples R China);Jacob, Timo (Ulm Univ, Germany);Björk, Jonas [jonbj66] [0000-0002-1345-0006] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Zhu, Junfa (Univ Sci and Technol China, Peoples R China);Qu, Xiaohui (Natl Ctr Nanosci and Technol, Peoples R China; Univ Chinese Acad Sci, Peoples R China);Xu, Wei (Tongji Univ, Peoples R China)","Direct Formation of C-C Double-Bonded Structural Motifs by On-Surface Dehalogenative Homocoupling of gem-Dibromomethyl Molecules","Artikel i tidskrift","Refereegranskat","eng","ACS Nano","1936-0851","1936-086X","published","12","8","","7959","7966","2018","","","","AMER CHEMICAL SOC","","","","","","","10.1021/acsnano.8b02459","000443525600047","30016072","","urn:nbn:se:liu:diva-151513","","","dehalogenative homocoupling; gem-dibromomethyl; scanning tunneling microscopy; noncontact atomic force microscopy; surface chemistry","Materialkemi (10403)","","","<p>Funding Agencies|National Natural Science Foundation of China [21473123, 21622307, 21790351, 51403157, 21603045, 21425310, 91427301]; Fundamental Research Funds for the Central Universities of China [2018XKJC-009]; International Cooperation Training Project Funding for Postgraduate of Tonggji University [2018XKJC-009]; Alexander von Humboldt Foundation</p>","<p>Conductive polymers are of great importance in a variety of chemistry-related disciplines and applications. The recently developed bottom-up on-surface synthesis strategy provides us with opportunities for the fabrication of various nanostructures in a flexible and facile manner, which could be investigated by high-resolution microscopic techniques in real space. Herein, we designed and synthesized molecular precursors functionalized with benzal gem-dibromomethyl groups. A combination of scanning tunneling microscopy, noncontact atomic force microscopy, high-resolution synchrotron radiation photoemission spectroscopy, and density functional theory calculations demonstrated that it is feasible to achieve the direct formation of C-C double-bonded structural motifs via on-surface dehalogenative homocoupling reactions on the Au(111) surface. Correspondingly, we convert the sp(3)-hybridized state to an sp(2)-hybridized state of carbon atoms, i.e., from an alkyl group to an alkenyl one. Moreover, by such a bottom-up strategy, we have successfully fabricated poly(phenylenevinylene) chains on the surface, which is anticipated to inspire further studies toward understanding the nature of conductive polymers at the atomic scale.</p>","","","","","","","","","","","","","2018-09-24","2018-09-24","2018-09-24","","","18","","1","","","","","","false","","","" "1248044","Gambino, Davide [davga91] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Max Planck Inst Eisenforsch GmbH, Germany)","Lattice relaxations in disordered Fe-based materials in the paramagnetic state from first principles","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","98","6","","","","2018","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.98.064105","000443139600004","","","urn:nbn:se:liu:diva-151199","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Research Council (VR) [2014-6336]; Marie Sklodowska Curie Actions, Cofund [INCA 600398]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFOMatLiU) [2009 00971]; Swedish Foundation for Strategic Research</p>","<p>The first-principles calculation of many material properties, in particular related to defects and disorder, starts with the relaxation of the atomic positions of the system under investigation. This procedure is routine for nonmagnetic and magnetically ordered materials. However, when it comes to magnetically disordered systems, in particular the paramagnetic phase of magnetic materials, it is not clear how the relaxation procedure should be performed or which geometry should be used. Here we propose a method for the structural relaxation of magnetic materials in the paramagnetic regime, in an adiabatic fast-magnetism approximation within the disordered local moment (DLM) picture in the framework of density functional theory. The method is straightforward to implement using any ab initio code that allows for structural relaxations. We illustrate the importance of considering the disordered magnetic state during lattice relaxations by calculating formation energies and geometries for an Fe vacancy and C insterstitial atom in body-centered cubic (bcc) Fe as well as bcc Fe1-xCrx random alloys in the paramagnetic state. In the vacancy case, the nearest neighbors to the vacancy relax toward the vacancy of 0.14 angstrom (-5% of the ideal bcc nearest-neighbor distance), which is twice as large as the relaxation in the ferromagnetic case. The vacancy formation energy calculated in the DLM state on these positions is 1.60 eV, which corresponds to a reduction of about 0.1 eV compared to the formation energy calculated using DLM but on ferromagnetic-relaxed positions. The carbon interstitial formation energy is found to be 0.41 eV when the DLM relaxed positions are used, as compared to 0.59 eV when the FM-relaxed positions are employed. For bcc Fe0.5Cr0.5 alloys, the mixing enthalpy is reduced by 5 meV/atom, or about 10%, when the DLM state relaxation is considered, as compared to positions relaxed in the ferromagnetic state.</p>","","","","","","","","","","","","","2018-09-13","2018-09-13","2018-10-05","http://liu.diva-portal.org/smash/get/diva2:1248044/FULLTEXT01.pdf","","2","","2","","","","","064105","false","","","" "1251748","Ekholm, Marcus [marek10] [0000-0002-7563-1494] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Gambino, Davide [davga91] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Jönsson, Johan [johjo06] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Tasnadi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Max Planck Inst Eisenforsch GmbH, Germany);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Natl Univ Sci and Technol MISIS, Russia)","Assessing the SCAN functional for itinerant electron ferromagnets","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","98","9","","","","2018","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.98.094413","000444348500004","","","urn:nbn:se:liu:diva-151640","","","","Teoretisk kemi (10407)","","","<p>Funding Agencies|Swedish e-Science Research Centre (SeRC); Swedish Research Council (VR) through the International Career Grant [20146336]; Marie Sklodowska CurieActions, Cofund, Project [INCA 600398]; Swedish Foundation for Strategic Research (SSF) through the Future Research Leaders 6 program; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; competence center FunMat-II - Vinnova [201605156]; Russian Science Foundation [18-12-00492]</p>","<p>Density functional theory is a standard model for condensed-matter theory and computational material science. The accuracy of density functional theory is limited by the accuracy of the employed approximation to the exchange-correlation functional. Recently, the so-called strongly constrained appropriately normed (SCAN) [Sun, Ruzsinszky, and Perdew, Phys. Rev. Lett. 115, 036402 (2015)] functional has received a lot of attention due to promising results for covalent, metallic, ionic, as well as hydrogen- and van der Waals-bonded systems alike. In this work, we focus on assessing the performance of the SCAN functional for itinerant magnets by calculating basic structural and magnetic properties of the transition metals Fe, Co, and Ni. We find that although structural properties of bcc-Fe seem to be in good agreement with experiment, SCAN performs worse than standard local and semilocal functionals for fcc-Ni and hcp-Co. In all three cases, the magnetic moment is significantly overestimated by SCAN, and the 3d states are shifted to lower energies, as compared to experiments.</p>","","","","","","","","","","","","","2018-09-27","2018-09-27","2018-10-19","http://liu.diva-portal.org/smash/get/diva2:1251748/FULLTEXT01.pdf","","6","","2","","","","","094413","false","","","" "1250676","Greenberg, Eran (Tel Aviv Univ, Israel; Univ Chicago, IL 60637 USA);Leonov, Ivan (Inst Met Phys, Russia; NUST MISIS, Russia);Layek, Samar (Tel Aviv Univ, Israel);Konopkova, Zuzana (PETRA III, Germany);Pasternak, Moshe P. (Tel Aviv Univ, Israel);Dubrovinsky, Leonid (Univ Bayreuth, Germany);Jeanloz, Raymond (Univ Calif Berkeley, CA 94720 USA);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (NUST MISIS, Russia);Rozenberg, Gregory Kh. (Tel Aviv Univ, Israel)","Pressure-Induced Site-Selective Mott Insulator-Metal Transition in Fe2O3","Artikel i tidskrift","Refereegranskat","eng","Physical Review X","2160-3308","2160-3308","published","8","3","","","","2018","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevX.8.031059","000444211800001","","","urn:nbn:se:liu:diva-151474","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Israeli Science Foundation [1189/14]; U.S. Department of Energy; Swedish Research Council (VR) [2015-04391]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFOMatLiU) [2009 00971]; Swedish e-Science Research Centre (SeRC); Deutsche Forschungsgemeinschaft through Transregio [TRR 80]; Russian Science Foundation [18-12-00492]; Ministry of Education and Science of the Russian Federation [K3-2016-027]</p>","<p>We provide experimental and theoretical evidence for a pressure-induced Mott insulator-metal transition in Fe2O3 characterized by site-selective delocalization of the electrons. Density functional plus dynamical mean field theory (DFT + DMFT) calculations, along with Mossbauer spectroscopy, x-ray diffraction, and electrical transport measurements on Fe2O3 up to 100 GPa, reveal this site-selective Mott transition between 50 and 68 GPa, such that the metallization can be described by ((FE3+HS)-F-VI)(2)O-3 [R (3) over barc structure]-amp;gt;(50) (GPa) (Fe-VIII(3+HS) Fe-VI(M))O-3 [P2(1)/n structure]-amp;gt;(68 Gpa)(Fe-VI(M))(2)O-3[Aba2/PPv structure]. Within the P2(1)/n crystal structure, characterized by two distinct coordination sites (VI and VIII), we observe equal abundances of ferric ions (Fe3+) and ions having delocalized electrons (Fe-M), and only at higher pressures is a fully metallic high-pressure structure obtained, all at room temperature. Thereby, the transition is characterized by delocalization/metallization of the 3d electrons on half the Fe sites, with a site-dependent collapse of local moments. Above approximately 50 GPa, Fe2O3 is a strongly correlated metal with reduced electron mobility (large band renormalizations) of m*/m similar to 4 and 6 near the Fermi level. Importantly, upon decompression, we observe a site-selective (metallic) to conventional Mott insulator phase transition (Fe-VIII(3+HS) Fe-VI(M))O-3 -amp;gt;(50) (GPa)(Fe-VIII(3+HS) Fe-VI(3+HS))O-3 within the same P2(1)/n structure, indicating a decoupling of the electronic and lattice degrees of freedom. Our results offer a model for understanding insulator-metal transitions in correlated electron materials, showing that the interplay of electronic correlations and crystal structure may result in rather complex behavior of the electronic and magnetic states of such compounds.</p>","","","","","","","","","","","","","2018-09-24","2018-09-24","2018-10-19","http://liu.diva-portal.org/smash/get/diva2:1250676/FULLTEXT01.pdf","","9","","1","","","","","031059","false","","","" "1259448","Gradov, O. M. (Russian Acad Sci, Russia);Stenflo, Lennart [lenst65] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Basic properties of nonlinear surface charge waves at a plasma boundary","Artikel i tidskrift","Refereegranskat","eng","Physics Letters A","0375-9601","1873-2429","published","42-43","","","3083","3085","2018","","","","ELSEVIER SCIENCE BV","","","","","","","10.1016/j.physleta.2018.08.018","000446145100006","","","urn:nbn:se:liu:diva-152052","","","Large amplitude oscillations; Plasma boundary; Solitary waves; Surface charge","Fusion, plasma och rymdfysik (10303)","","","","<p>The nonlinear properties of surface charges are here analyzed under ideal conditions. We thus deduce a new single equation from the wellknown equations which govern the cold electron plasma motion. Simple formulas that describe the propagation of surface charge perturbations along the plasma boundary are also found. (C) 2018 Elsevier B.V. All rights reserved.</p>","","","","","","","","","","","","","2018-10-29","2018-10-29","2018-10-29","","","2","","1","","","","","","false","","","" "1254061","Fallqvist, Amie [amifa57] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Institutionen för teknik och naturvetenskap [296]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Olovsson, Weine [weiol14] (Linköpings universitet [276], Nationellt superdatorcentrum (NSC) [16051]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Max Planck Inst Eisenforsch GmbH, Germany);Palisaitis, Justinas [juspa01] [0000-0003-3203-7935] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Belov, M. P. (Natl Univ Sci and Technol MISIS, Russia);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Hultman, Lars [larhu75] [0000-0002-2837-3656] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Persson, Per O A [perpe25] [0000-0001-9140-6724] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Resolving the debated atomic structure of the metastable cubic SiNx tissue phase in nanocomposites with TiN","Artikel i tidskrift","Refereegranskat","eng","Physical Review Materials","2475-9953","","published","2","9","","","","2018","","","","American Physical Society","","","","","","","10.1103/PhysRevMaterials.2.093608","000445181600001","","","urn:nbn:se:liu:diva-151780","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Research Council (VR) [2008-405, 2012-4359, 2015-04391, 2016-04412]; Swedish Foundation for Strategic Research (SSF) through FunCase; SRL [10-0026]; M. Bergwall foundation; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005, K2-2017-080]; [RIF 14-0074]</p>","<p>The TiN/SiNx nanocomposite and nanolaminate systems are the archetype for super if not ultrahard materials. Yet, the nature of the SiNx tissue phase is debated. Here, we show by atomically resolved electron microscopy methods that SiNx is epitaxially stabilized in a NaCl structure on the adjacent TiN(001) surfaces. Additionally, electron energy loss spectroscopy, supported by first-principles density functional theory calculations infer that SiNx hosts Si vacancies.</p>","","","","","","","","","","","","","2018-10-08","2018-10-08","2018-11-14","http://liu.diva-portal.org/smash/get/diva2:1254061/FULLTEXT01.pdf","","8","","0","","","","","093608","true","","","" "1256352","Stockem, Irina [irist97] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Max Planck Inst Eisenforsch GmbH, Germany);Bergman, Anders (Univ Versailles, France; CEA, France);Glensk, Albert (Max Planck Inst Eisenforsch GmbH, Germany);Hickel, Tilmann (Max Planck Inst Eisenforsch GmbH, Germany);Koermann, Fritz (Max Planck Inst Eisenforsch GmbH, Germany; Delft Univ Technol, Netherlands);Grabowski, Blazej (Max Planck Inst Eisenforsch GmbH, Germany);Neugebauer, Joerg (Max Planck Inst Eisenforsch GmbH, Germany);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Max Planck Inst Eisenforsch GmbH, Germany)","Anomalous Phonon Lifetime Shortening in Paramagnetic CrN Caused by Spin-Lattice Coupling: A Combined Spin and Ab Initio Molecular Dynamics Study","Artikel i tidskrift","Refereegranskat","eng","Physical Review Letters","0031-9007","1079-7114","published","121","12","","","","2018","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevLett.121.125902","000445326500007","30296117","","urn:nbn:se:liu:diva-151943","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|FP7 Marie Sklodowska-Curie COFUND Programme [600382]; priority programme SPP1599 ""Ferroic cooling"" [HI1300/6-2]; Netherlands Organisation for Scientific Research (NWO) under the VIDI research programme [15707]; European Research Council (ERC) under the EUs Horizon 2020 Research and Innovation Programme [639211]; Swedish Research Council (VR) [330-2014-6336]; Marie Sklodowska Curie Actions [INCA 600398]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFOMatLiU) [2009 00971]; Swedish Foundation for Strategic Research</p>","<p>We study the mutual coupling of spin fluctuations and lattice vibrations in paramagnetic CrN by combining atomistic spin dynamics and ab initio molecular dynamics. The two degrees of freedom are dynamically coupled, leading to nonadiabatic effects. Those effects suppress the phonon lifetimes at low temperature compared to an adiabatic approach. The dynamic coupling identified here provides an explanation for the experimentally observed unexpected temperature dependence of the thermal conductivity of magnetic semiconductors above the magnetic ordering temperature.</p>","","","","","","","","","","","","","2018-10-16","2018-10-16","2018-11-14","http://liu.diva-portal.org/smash/get/diva2:1256352/FULLTEXT01.pdf","","8","","2","","","","","125902","false","","","" "1265296","Mosyagin, Igor [igomo87] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (NUST MISIS, Russia);Gambino, Davide [davga91] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Sangiovanni, Davide [davsa82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Ruhr Univ Bochum, Germany);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (NUST MISIS, Russia);Caffrey, Nuala M. [n/a] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Trinity Coll Dublin, Ireland)","Effect of dispersion corrections on ab initio predictions of graphite and diamond properties under pressure","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","98","17","","","","2018","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.98.174103","000449514900001","","","urn:nbn:se:liu:diva-152804","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Research Council (VR) [2015-04391, 2014-4750, 637-2013-7296]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]; Russian Science Foundation [18-12-00492]; Olle Engkvist Foundation; Science Foundation Ireland Starting Investigator Research Grant [15/SIRG/3314]</p>","<p>There are several approaches to the description of van der Waals (vdW) forces within density functional theory. While they are generally found to improve the structural and energetic properties of those materials dominated by weak dispersion forces, it is not known how they behave when the material is subject to an external pressure. This could be an issue when considering the pressure-induced structural phase transitions, which are currently attracting great attention following the discovery of an ultrahard phase formed by the compression of graphite at room temperature. In order to model this transition, the functional must be capable of simultaneously describing both strong covalent bonds and weak dispersion interactions as an isotropic pressure is applied. Here, we report on the ability of several dispersion-correction functionals to describe the energetic, structural, and elastic properties of graphite and diamond, when subjected to an isotropic pressure. Almost all of the tested vdW corrections provide an improved description of both graphite and diamond compared to the local density approximation. The relative error does not change significantly as pressure is applied, and in some cases even decreases. We therefore conclude that the use of dispersion-corrected exchange-correlation functionals, which have been neglected to date, will improve the accuracy and reliability of theoretical investigations into the pressure-induced phase transition of graphite.</p>","","","","","","","","","","","","","2018-11-22","2018-11-22","2018-11-22","","","5","","2","","","","","174103","false","","","" "1267324","Bykova, E. (DESY, Germany; Univ Bayreuth, Germany);Bykov, M. (Univ Bayreuth, Germany; Natl Univ Sci and Technol MISIS, Russia);Cernok, A. (Univ Bayreuth, Germany; Open Univ, England);Tidholm, Johan [johti34] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Hellman, Olle [olohe96] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (CALTECH, CA 91125 USA);Belov, M. P. (Natl Univ Sci and Technol MISIS, Russia);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Liermann, H. -P. (DESY, Germany);Hanfland, M. (European Synchrotron Radiat Facil, France);Prakapenka, V. B. (Univ Chicago, IL 60637 USA);Prescher, C. (Univ Chicago, IL 60637 USA; Univ Cologne, Germany);Dubrovinskaia, N. (Univ Bayreuth, Germany);Dubrovinsky, L. (Univ Bayreuth, Germany)","Metastable silica high pressure polymorphs as structural proxies of deep Earth silicate melts","Artikel i tidskrift","Refereegranskat","eng","Nature Communications","2041-1723","2041-1723","published","9","","","","","2018","","","","NATURE PUBLISHING GROUP","","","","","","","10.1038/s41467-018-07265-z","000450160100002","30442940","","urn:nbn:se:liu:diva-153165","","","","Materialkemi (10403)","","","<p>Funding Agencies|German Research Foundation [Deutsche Forschungsgemeinschaft (DFG)]; Federal Ministry of Education and Research [ Bundesministerium fur Bildung und Forschung (BMBF), Germany] [DU 954-11/1, DU 393-9/2, DU 393-10/1, 5K16WC1]; National Science Foundation-Earth Sciences [EAR-1634415]; Department of Energy-GeoSciences [DE-FG02-94ER14466]; DOE Office of Science by Argonne National Laboratory [DE-AC02-06CH11357]; Elite Network of Bavaria through the program Oxides; Swedish Research Council [2015-04391, 2014-4750, 637-2013-7296]; Swedish Government Strategic Research Areas in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [200900971]; Swedish e-Science Research Centre (SeRC); Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of NUST ""MISIS"" [K2-2017-080]</p>","<p>Modelling of processes involving deep Earth liquids requires information on their structures and compression mechanisms. However, knowledge of the local structures of silicates and silica (SiO2) melts at deep mantle conditions and of their densification mechanisms is still limited. Here we report the synthesis and characterization of metastable high-pressure silica phases, coesite-IV and coesite-V, using in situ single-crystal X-ray diffraction and ab initio simulations. Their crystal structures are drastically different from any previously considered models, but explain well features of pair-distribution functions of highly densified silica glass and molten basalt at high pressure. Built of four, five-, and six-coordinated silicon, coesite-IV and coesite-V contain SiO6 octahedra, which, at odds with 3rd Paulings rule, are connected through common faces. Our results suggest that possible silicate liquids in Earths lower mantle may have complex structures making them more compressible than previously supposed.</p>","","","","","","","","","","","","","2018-12-01","2018-12-01","2018-12-01","","","14","","2","","","","","4789","false","","","" "1262092","Ektarawong, Annop [annek02] [0000-0002-6059-6833] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Max Planck Inst Eisenforsch GmbH, Germany)","Effect of temperature and configurational disorder on the electronic band gap of boron carbide from first principles","Artikel i tidskrift","Refereegranskat","eng","PHYSICAL REVIEW MATERIALS","2475-9953","","published","2","10","","","","2018","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevMaterials.2.104603","000447735500002","","","urn:nbn:se:liu:diva-152617","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Research Council (VR) [2014-6336, 2014-4750]; Marie Sklodowska Curie Actions, Cofund [INCA 600398]; Swedish Foundation for Strategic Research (SSF) through the Future Research Leaders 6 program; Kungl. Ingenjorsvetenskapsakademiens Hans Werthen-Fond; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]</p>","<p>The overestimation, rather than the usual underestimation, of the electronic band gap at 0 K of boron carbide with the ideally stoichiometric composition of B4C, represented by B11CP (CBC), in density functional theory calculations is one of the outstanding controversial issues in the field of icosahedral boron-rich solids. Using a first-principles approach, we explore the effect of temperature and configurational disorder on the electronic band gap of B4C. Ab initio molecular dynamics simulations are performed to account for the effects of vibrational disorder. The results reveal that the volumetric thermal expansion as well as the thermally induced configurational disorder of icosahedral C-P atoms residing in the B11CP icosahedra have a minimal impact on the band gap of B4C, while a major decrease of the band gap is caused by explicit atomic displacements, induced by lattice vibrations. At 298 K, the band gap of B4C is overestimated, as compared to the experimental value, by approximately 31%. However, configurational disorder induced by introducing a small fraction of B-12 (CBC) and B-12 (B-4) into a matrix of B11CP (CBC) to make the composition of boron carbide approximately B4.3C, claimed to be the carbon-rich limit of the material in experiment, leads to a smaller band gap due to the appearance of midgap states. These results can explain at least a part of the previous discrepancies between theory and experiments for the band gap of boron carbide.</p>","","","","","","","","","","","","","2018-11-09","2018-11-09","2018-12-03","http://liu.diva-portal.org/smash/get/diva2:1262092/FULLTEXT01.pdf","","3","","0","","","","","104603","false","","","" "1273226","Szymanski, N. J. (Univ Toledo, OH 43606 USA);Walters, L. N. (Northwestern Univ, IL 60208 USA);Hellman, Olle [olohe96] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (CALTECH, CA 91125 USA);Gall, D. (Rensselaer Polytech Inst, NY 12180 USA);Khare, S. V. (Univ Toledo, OH 43606 USA)","Dynamical stabilization in delafossite nitrides for solar energy conversion","Artikel i tidskrift","Refereegranskat","eng","Journal of Materials Chemistry A","2050-7488","","published","6","42","","20852","20860","2018","","","","ROYAL SOC CHEMISTRY","","","","","","","10.1039/c8ta07536k","000451600200029","","","urn:nbn:se:liu:diva-153534","","","","Oorganisk kemi (10404)","","","<p>Funding Agencies|National Science Foundation under CMMI [1629230, 1629239]; National Science Foundation under EFRI-2DARE program [1433467]; Air Force Research Laboratory, Space Vehicles Directorate [FA9453-11-C-0253]</p>","<p>Delafossite structured ternary nitrides, ABN(2), have been of recent experimental investigation for applications such as tandem solar and photoelectrochemical cells. We present a thorough first principles computational investigation of their stability, electronic structure, and optical properties. Nine compounds, where A = Cu, Ag, Au and B = V, Nb, Ta, were studied. For three of these compounds, CuTaN2, CuNbN2, and AgTaN2, our computations agree well with experimental results. Optimized lattice parameters, formation energies, and mechanical properties have been computed using the generalized gradient approximation (GGA). Phonon density of states computed at zero-temperature shows that all compounds are dynamically unstable at low temperatures. Including finite-temperature anharmonic effects stabilizes all compounds at 300 K, with the exception of AgVN2. Analysis of Crystal Orbital Hamiltonian Populations (COHP) provides insight into the bonding and antibonding characters of A-N and B-N pairs. Instability at low temperatures can be attributed to strong A-N antibonding character near the Fermi energy. B-N bonding is found to be crucial in maintaining stability of the structure. AgVN2 is the only compound to display significant B-N antibonding below the Fermi energy, as well as the strongest degree of A-N antibonding, both of which provide explanation for the sustained instability of this compound up to 900 K. Hybrid functional calculations of electronic and optical properties show that real static dielectric constants in the semiconductors are related to corresponding band gaps through the Moss relation. CuTaN2, CuNbN2, AgTaN2, AgNbN2, AgVN2, AuTaN2, and AuNbN2 exhibit indirect electronic band gaps while CuVN2 and AuVN2 are metallic. Imaginary parts of the dielectric function are characterized by d-d interband transitions in the semiconductors and d-d intraband transitions in the metals. Four compounds, CuTaN2, CuNbN2, AgTaN2, and AgNbN2, are predicted to exhibit large light absorption in the range of 1.0 to 1.7 eV, therefore making these materials good candidates for solar-energy conversion applications. Two compounds, AuTaN2 and AuNbN2, have band gaps and absorption onsets near the ideal range for obtaining high solar-cell conversion efficiency, suggesting that these compounds could become potential candidates as absorber materials in tandem solar cells or for band-gap engineering by alloying.</p>","","","","","","","","","","","","","2018-12-20","2018-12-20","2018-12-20","","","5","","1","","","","","","false","","","" "1273233","Klarbring, Johan [johkl85] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Phase Stability of Dynamically Disordered Solids from First Principles","Artikel i tidskrift","Refereegranskat","eng","Physical Review Letters","0031-9007","1079-7114","published","121","22","","","","2018","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevLett.121.225702","000451581600011","30547633","","urn:nbn:se:liu:diva-153532","","","","Oorganisk kemi (10404)","","","<p>Funding Agencies|Swedish Research Council (VR) [2014-4750]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]</p>","<p>Theoretical studies of phase stability in solid materials with dynamic disorder are challenging due to the failure of the standard picture of atoms vibrating around fixed equilibrium positions. Dynamically disordered solid materials show immense potential in applications. In particular, superionic conductors, where the disorder results in exceptionally high ionic conductivity, are very promising as solid state electrolytes in batteries and fuel cells. The biggest obstacle in living up to this potential is the limited stability of the dynamically disordered phases. Here, we outline a method to obtain the free energy of a dynamically disordered solid. It is based on a stress-strain thermodynamic integration on a deformation path between a mechanically stable ordered variant of the disordered phase, and the dynamically disordered phase itself. We show that the large entropy contribution associated with the dynamic disorder is captured in the behavior of the stress along the deformation path. We apply the method to Bi2O3, whose superionic delta phase is the fastest known solid oxide ion conductor. We accurately reproduce the experimental transition enthalpy and the critical temperature of the phase transition from the low temperature ground state a phase to the superionic d phase. The method can be used for a first-principles description of the phase stability of superionic conductors and other materials with dynamic disorder, when the disordered phase can be connected to a stable phase through a continuous deformation path.</p>","","","","","","","","","","","","","2018-12-20","2018-12-20","2018-12-20","","","2","","2","","","","","225702","false","","","" "1274648","Herriman, Jane E. (CALTECH, CA 91125 USA);Hellman, Olle [olohe96] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (CALTECH, CA 91125 USA);Fultz, Brent (CALTECH, CA 91125 USA)","Phonon thermodynamics and elastic behavior of GaN at high temperatures and pressures","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","98","21","","","","2018","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.98.214105","000452324400001","","","urn:nbn:se:liu:diva-153500","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Office of Science of the U.S. Department of Energy [DE-AC02-05CH11231]; Department of Energy through the Carnegie-DOE Alliance Centers Stewardship Sciences Academic Alliance Program; Department of Energy through Office of Science Graduate Fellowship Program (DOE SCGF) [DE-AC05-06OR23100]</p>","<p>The effects of temperature and pressure on the phonons of GaN were calculated for both the wurtzite and zinc-blende structures. The quasiharmonic approximation (QHA) gave reasonable results for the temperature dependence of the phonon DOS at zero pressure but unreliably predicted the combined effects of temperature and pressure. Pressure was found to change the explicit anharmonicity, altering the thermal shifts of phonons and more notably qualitatively changing the evolution of phonon lifetimes with increasing temperature. These effects were largest for the optical modes, and phonon frequencies below approximately 5 THz were adequately predicted with the QHA. The elastic anisotropies of GaN in both wurtzite and zinc-blende structures were calculated from the elastic constants as a function of pressure at 0 K. The elastic anisotropy increased with pressure until reaching elastic instabilities at 40 GPa (zinc blende) and 65 GPa (wurtzite). The calculated instabilities are consistent with proposed transformation pathways to rocksalt GaN and place upper bounds on the pressures at which wurtzite and zinc-blende GaN can be metastable.</p>","","","","","","","","","","","","","2019-01-02","2019-01-02","2019-01-02","","","3","","2","","","","","214105","false","","","" "1276241","Hansson, Tobias [tobha84] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Univ Brescia, Italy);Parra-Rivas, Pedro (Univ Libre Bruxelles, Belgium; Univ Leuven, Belgium);Bernard, Martino (Univ Brescia, Italy);Leo, Francois (Univ Libre Bruxelles, Belgium);Gelens, Lendert (Univ Leuven, Belgium);Wabnitz, Stefan (Univ Brescia, Italy; CNR INO, Italy)","Quadratic soliton combs in doubly resonant second-harmonic generation","Artikel i tidskrift","Refereegranskat","eng","Optics Letters","0146-9592","1539-4794","published","43","24","","6033","6036","2018","","","","OPTICAL SOC AMER","","","","","","","10.1364/OL.43.006033","000453212500033","30547998","","urn:nbn:se:liu:diva-153670","","","","Atom- och molekylfysik och optik (10302)","","","<p>Funding Agencies|H2020 Marie Sklodowska-Curie Actions (MSCA) [GA-2015-713694]; Vetenskapsradet (VR) [2017-05309]; Ministero dellIstruzione, dellUniversita e della Ricerca (MIUR) [2015KEZNYM-NEMO]; European Research Council (ERC) [757800]; KU Leuven</p>","<p>We report a theoretical investigation of quadratic frequency combs in a dispersive second-harmonic generation cavity system. We identify different dynamical regimes and demonstrate that the same system can exhibit both bright and dark localized cavity solitons in the absence of a temporal walk-off. (c) 2018 Optical Society of America</p>","","","","","","","","","","","","","2019-01-07","2019-01-07","2019-01-07","","","6","","2","","","","","","false","","","" "1068924","Tasnadi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Lugovskoy, Andrey V. (NUST MISIS, Russia);Odén, Magnus [magod41] [0000-0002-2286-5588] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (NUST MISIS, Russia)","Non-equilibrium vacancy formation energies in metastable alloys - A case study of Ti0.5Al0.5N","Artikel i tidskrift","Refereegranskat","eng","MATERIALS and DESIGN","0264-1275","","published","114","","","484","493","2017","","","","ELSEVIER SCI LTD","","","","","","","10.1016/j.matdes.2016.10.071","000390650800058","","","urn:nbn:se:liu:diva-134066","","","Metastable materials; Non-equilibrium; Vacancy formation energy; Hard coatings; Supercell approach","Metallurgi och metalliska material (20506)","","","<p>Funding Agencies|Swedish Foundation for Strategic Research (SSF) project Designed Multicomponent coatings (MultiFilms); SRL Grant [10-0026]; M-ERA.NET Multiscale Computational-design of novel hard nanostructure Coatings (MC2) project; Swedish Research Council (VR) [2015-04391]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]</p>","<p>In this study, we present a computational technique to investigate non-equilibrium vacancies in metastable alloys. In contrast to equilibrium materials, calculation of the energy of removing an alloying atom requires a finite size configurational correction. We explain that in metastable alloys the vacancy formation energy is defined up to an arbitrary constant. We argue that in non-equilibrium alloys no statistical considerations are required and there is a distribution of the vacancy formation energy with large variation. We show for the example of Ti0.5Al0.5N that the configuration correction is significant. Using cluster expansion, we demonstrate the major importance of the first two metallic coordination shells in Ti0.5Al0.5N. We introduce a three-dimensional representation of the energies of removing Ti and Al atoms as a function of number of Al atoms in the neighboring shells and we predict the metal atom vacancy formation energy in arbitrary local chemical environments. Neglecting the interactions between the vacant sites and assuming their simultaneous occurrence, we show how to extract information about the energy cost of a vacancy concentration in metastable alloys. We conclude that in metastable disordered alloys vacancies should occur in local environments that correspond to the lowest formation energies rather than distributed statistically. (C) 2016 Elsevier Ltd. All rights reserved.</p>","","","","","","","","","","","","","2017-01-22","2017-01-26","2017-01-26","","","4","","0","","","","","","false","","","" "1071711","Mukhamedov, B. O. (National University of Science and Technology MISIS, Russia);Ponomareva, A. V. (National University of Science and Technology MISIS, Russia);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Spinodal decomposition in ternary Fe-Cr-Co system","Artikel i tidskrift","Refereegranskat","eng","JOURNAL OF ALLOYS AND COMPOUNDS","0925-8388","","published","695","","","250","256","2017","","","","ELSEVIER SCIENCE SA","","","","","","","10.1016/j.jallcom.2016.10.185","000391817600031","","","urn:nbn:se:liu:diva-134299","","","First-principles simulations; Spinodal decomposition; Fe-Cr-Co alloys","Metallurgi och metalliska material (20506)","","","<p>Funding Agencies|Ministry of Education and Science of the Russian Federation [RFMEFI58715X0023]; Swedish Foundation for Strategic Research (SSF) program SRL [10-0026]</p>","<p>Using the exact muffin-tin orbitals method in conjunction with the coherent potential approximation we have studied the tendency towards spinodal decomposition of solid solution in ternary Fe-Cr-Co system. In addition, we have estimated the Curie temperature of the alloys, and considered the influence of the magnetic state on the decomposition thermodynamics of the ternary alloys. Using the mean field approximation, we have estimated the finite temperature effects on the alloys free energy. We predict that an increase Co and Cr content in the ternary Fe-Cr-Co system increases the tendency of the bcc (alpha)-FexCryCoz alloys towards the spinodal decomposition. Because of this, high magnetic properties and high thermal stability of these properties can be expected in the Fe-Cr-Co alloys with high Co content. (C) 2016 Elsevier B.V. All rights reserved.</p>","","","","","","","","","","","","","2017-02-03","2017-02-06","2017-02-06","","","3","","0","","","","","","false","","","" "1071706","Shulumba, Nina (CALTECH, CA 91125 USA);Hellman, Olle [olohe96] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (CALTECH, CA 91125 USA);Minnich, Austin J. (CALTECH, CA 91125 USA)","Intrinsic localized mode and low thermal conductivity of PbSe","Artikel i tidskrift","Refereegranskat","eng","PHYSICAL REVIEW B","2469-9950","","published","95","1","","","","2017","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.95.014302","000391305600003","","","urn:nbn:se:liu:diva-134301","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|DARPA MATRIX program [HR0011-15-2-0039]; Swedish Research Council (VR) program [637-2013-7296]; National Science Foundation [ACI-1053575]; Swedish National Infrastructure for Computing (SNIC) at PDC Center (High Performance Computing at the KTH Royal Institute of Technology); National Supercomputer Centre (NSC) at Linkoping University</p>","<p>Lead chalcogenides such as PbS, PbSe, and PbTe are of interest for their exceptional thermoelectric properties and strongly anharmonic lattice dynamics. Although PbTe has received the most attention, PbSe has a lower thermal conductivity and a nonlinear temperature dependence of thermal resistivity despite being stiffer, trends that prior first-principles calculations have not fully reproduced. Here, we use ab initio calculations that explicitly account for strong anharmonicity and a computationally efficient stochastic phase-space sampling scheme to identify the origin of this low thermal conductivity as an anomalously large anharmonic interaction, exceeding in strength that in PbTe, between the transverse optic and longitudinal acoustic branches. The strong anharmonicity is reflected in the striking observation of an intrinsic localized mode that forms in the acoustic frequencies. Our work shows the deep insights into thermal phonons that can be obtained from ab initio calculations that do not rely on perturbations from the ground-state phonon dispersion.</p>","","","","","","","","","","","","","2017-02-03","2017-02-06","2017-02-22","http://liu.diva-portal.org/smash/get/diva2:1071706/FULLTEXT01.pdf","","3","","0","","","","","014302","false","","","" "1089993","Brodin, G. (Umeå University, Sweden);Stenflo, Lennart [lenst65] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","A simple electron plasma wave","Artikel i tidskrift","Refereegranskat","eng","Physics Letters A","0375-9601","1873-2429","published","381","11","","1033","1035","2017","","","","ELSEVIER SCIENCE BV","","","","","","","10.1016/j.physleta.2016.11.034","000395230300015","","","urn:nbn:se:liu:diva-136586","","","Large amplitude waves; Plasma oscillations; Parametric processes","Fusion, plasma och rymdfysik (10303)","","","","<p>Considering a class of solutions where the density perturbations are functions of time, but not of space, we derive a new exact large amplitude wave solution for a cold uniform electron plasma. This result illustrates that most simple analytical solutions can appear even if the density perturbations are large. (C) 2016 Elsevier B.V. All rights reserved.</p>","","","","","","","","","","","","","2017-04-21","2017-04-21","2017-04-21","","","2","","1","","","","","","false","","","" "1093272","Ribeiro, Luiz Antonio [luiri41] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Brasilia, Brazil);Ferreira da Cunha, Wiliam (University of Brasilia, Brazil);Luciano de Almeida Fonseca, Antonio (University of Brasilia, Brazil);Magela e Silva, Geraldo (University of Brasilia, Brazil)","Bloch oscillations in organic and inorganic polymers","Artikel i tidskrift","Refereegranskat","eng","Journal of Chemical Physics","0021-9606","1089-7690","published","146","14","","","","2017","","","","AMER INST PHYSICS","","","","","","","10.1063/1.4979950","000399078700032","28411599","","urn:nbn:se:liu:diva-137088","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|CNPq; CAPES; FAP-DF; FINATEC; Brazilian Research Council FAP-DF Grant [0193.000942/2015]; Brazilian Ministry of Planning [DIPLA 005/2016]</p>","<p>The transport of polarons above the mobility threshold in organic and inorganic polymers is theoretically investigated in the framework of a one-dimensional tight-binding model that includes lattice relaxation. The computational approach is based on parameters for which the model Hamiltonian suitably describes different polymer lattices in the presence of external electric fields. Our findings show that, above critical field strengths, a dissociated polaron moves through the polymer lattice as a free electron performing Bloch oscillations. These critical electric fields are considerably smaller for inorganic lattices in comparison to organic polymers. Interestingly, for inorganic lattices, the free electron propagates preserving charge and spin densities localization which is a characteristic of a static polaron. Moreover, in the turning points of the spatial Bloch oscillations, transient polaron levels are formed inside the band gap, thus generating a fully characterized polaron structure. For the organic case, on the other hand, no polaron signature is observed: neither in the shape of the distortion-those polaron profile signatures are absent-nor in the energy levels-as no such polaron levels are formed during the simulation. These results solve controversial aspects concerning Bloch oscillations recently reported in the literature and may enlighten the understanding about the charge transport mechanism in polymers above their mobility edge. Published by AIP Publishing.</p>","","","","","","","","","","","","","2017-05-05","2017-05-05","2017-05-05","","","4","","1","","","","","144903","false","","","" "1076017","Edström, Daniel [daned22] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Sangiovanni, Davide [davsa82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Ruhr University of Bochum, Germany);Hultman, Lars [larhu75] [0000-0002-2837-3656] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Petrov, Ivan [ivape26] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Illinois, IL 61801 USA);Greene, Joseph E [josgr17] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Illinois, IL 61801 USA);Chirita, Valeriu [valch35] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Effects of incident N atom kinetic energy on TiN/TiN(001) film growth dynamics: A molecular dynamics investigation","Artikel i tidskrift","Refereegranskat","eng","Journal of Applied Physics","0021-8979","1089-7550","published","121","2","","","","2017","","","","AMER INST PHYSICS","","","","","","","10.1063/1.4972963","000392840000045","","","urn:nbn:se:liu:diva-134601","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Research Council (VR) Linkoping Linnaeus Initiative LiLi-NFM [2008-6572, 2009-00971, 2013-4018, 2014-5790]; Swedish Government Strategic Research Area Grant in Materials Science on Advanced Functional Materials; Knut and Alice Wallenberg Foundation [2011-KAW]; Olle Engkvist Foundation</p>","<p>Large-scale classical molecular dynamics simulations of epitaxial TiN/TiN(001) thin film growth at 1200 K, a temperature within the optimal range for epitaxial TiN growth, with an incident N-to-Ti flux ratio of four, are carried out using incident N energies E-N = 2 and 10 eV and incident Ti energy E-Ti = 2 eV. To further highlight the effect of E-N, we grow a bilayer film with E-N = 2 eV initially and then switch to E-N = 10 eV. As-deposited layers are analyzed as a function of composition, island-size distribution, island-edge orientation, and vacancy formation. Results show that growth with E-N = 2 eV results in films that are globally overstoichiometric with islands bounded by N-terminated polar 110 edges, whereas films grown with E-N = 10 eV are flatter and closer to stoichiometric. However, E-N = 10 eV layers exhibit local N deficiency leading to the formation of isolated 111-oriented islands. Films grown by changing the incident energy from 2 to 10 eV during growth are more compact than those grown entirely with E-N = 2 eV and exhibit greatly reduced concentrations of upper-layer adatoms, admolecules, and small clusters. Islands with 110 edges formed during growth with E-N = 2 eV transform to islands with 100 edges as E-N is switched to 10 eV. Published by AIP Publishing.</p>","","","","","","","","","","","","","2017-02-21","2017-02-21","2017-05-05","http://liu.diva-portal.org/smash/get/diva2:1076017/FULLTEXT01.pdf","","6","","1","","","","","025302","false","","","" "1096690","Ribeiro, Luiz Antonio [luiri41] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Brasilia, Brazil);Ferreira da Cunha, Wiliam (University of Brasilia, Brazil)","Nonadiabatic dynamics of injected holes in conjugated polymers","Artikel i tidskrift","Refereegranskat","eng","Physical Chemistry, Chemical Physics - PCCP","1463-9076","1463-9084","published","19","15","","10000","10008","2017","","","","ROYAL SOC CHEMISTRY","","","","","","","10.1039/c7cp00729a","000399383100032","28362447","","urn:nbn:se:liu:diva-137388","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|CNPq; CAPES; FINATEC; Brazilian Research Council FAPDF [0193.000942/2015]; Brazilian Ministry of Planning, Budget and Management [DIPLA 005/2016]</p>","<p>The dynamics of injected holes in short transient times that precede polaron formation is numerically studied in the framework of a tight-binding electron-phonon interacting approach aimed at describing organic one-dimensional lattices. In particular, the direct impact of internal and external factors on the conversion of injected holes into polarons is carefully investigated. The results show that a hole injected at levels lower than the highest occupied molecular orbital forms self-trapped bound structures that can merge spontaneously to form a polaron after, at least, one picosecond. On the other hand, the life-time of such structures substantially decreases (up to a few hundreds of femtoseconds) when the influence of external electric fields, temperature effects and impurities is considered. Importantly, the critical values of the aforementioned factors in promoting the quenching of the self-trapped structures are obtained. These findings may enlighten the understanding of the mechanism of charge carrier generation in Polymer Light Emitting Diodes when several kinds of excitations are present.</p>","","","","","","","","","","","","","2017-05-18","2017-05-18","2017-05-18","","","2","","2","","","","","","false","","","" "1090306","Belonoshko, Anatoly B. (Royal Institute Technology KTH, Sweden);Lukinov, Timofei (Royal Institute Technology KTH, Sweden);Fu, Jie (Royal Institute Technology KTH, Sweden; Dalian University of Technology, Peoples R China);Zhao, Jijun (Dalian University of Technology, Peoples R China);Davis, Sergio (Chilean Comm Nucl Energy CCHEN, Chile);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Stabilization of body-centred cubic iron under inner-core conditions","Artikel i tidskrift","Refereegranskat","eng","Nature Geoscience","1752-0894","1752-0908","published","10","4","","312","+","2017","","","","NATURE PUBLISHING GROUP","","","","","","","10.1038/NGEO2892","000398162800021","","","urn:nbn:se:liu:diva-136573","","","","Geokemi (10506)","","","<p>Funding Agencies|Swedish Research Council (VR) [2013-5767, 2014-4750]; National Magnetic Confinement Fusion Program of China [2015GB118000]; China Scholarship Council; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]</p>","<p>The Earths solid core is mostly composed of iron. However, despite being central to our understanding of core properties, the stable phase of iron under inner-core conditions remains uncertain. The two leading candidates are hexagonal close-packed and body-centred cubic (bcc) crystal structures, but the dynamic and thermodynamic stability of bcc iron under inner-core conditions has been challenged. Here we demonstrate the stability of the bcc phase of iron under conditions consistent with the centre of the core using ab initio molecular dynamics simulations. We find that the bcc phase is stabilized at high temperatures by a diffusion mechanism that arises due to the dynamical instability of the phase at lower temperatures. On the basis of our simulations, we reinterpret experimental data as support for the stability of bcc iron under inner-core conditions. We suggest that the diffusion of iron atoms in solid state may explain both the anisotropy and the low shear modulus of the inner core.</p>","","","","","","","","","","","","","2017-04-24","2017-04-24","2017-05-21","","","6","","2","","","","","","false","","","" "1097355","Cirera, B. (IMDEA Nanosci, Spain);Björk, Jonas [jonbj66] [0000-0002-1345-0006] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Otero, R. (IMDEA Nanosci, Spain; University of Autonoma Madrid, Spain);Gallego, J. M. (CSIC, Spain);Miranda, R. (IMDEA Nanosci, Spain; University of Autonoma Madrid, Spain);Ecija, D. (IMDEA Nanosci, Spain)","Efficient Lanthanide Catalyzed Debromination and Oligomeric Length-Controlled Ullmann Coupling of Aryl Halides","Artikel i tidskrift","Refereegranskat","eng","The Journal of Physical Chemistry C","1932-7447","1932-7455","published","121","14","","8033","8041","2017","","","","AMER CHEMICAL SOC","","","","","","","10.1021/acs.jpcc.7b02172","000399629000049","","","urn:nbn:se:liu:diva-137611","","","","Organisk kemi (10405)","","","<p>Funding Agencies|EC FP7-PEOPLE-COFUND AMAROUT II program; Spanish Ramon and Cajal Program [RYC-2012-11133]; Spanish Ministerio de Economia y Competitividad [FIS 2013-40667-P, FIS 2015-67287-P]; Comunidad de Madrid (projects MAD2D, NANOFRONTMAG) [52013/MT-2850]; IMDEA Foundation</p>","<p>Lanthanide elements play a vital role in a broad range of high-tech applications, and there is an increasing interest in their catalytic activity, particularly in organo-metallics. However, their catalytic role on surfaces remains unexplored. Here, we present a scanning tunneling microscopy and density functional theory study of the debromination, contacting, and coupling of dibromine terphenyl species with Dy (f-block element) and Ag (d-block element) adatoms, respectively. We show that Dy debrominates the targeted species more efficiently than Ag adatoms at room temperature, promoting the formation of unprecedented C-Dy-C organo-metallic supramolecules versus C-Ag-C parallel chains for the Ag case. DFT calculations corroborate our results showing an almost spontaneous debromination process with Dy compared to Ag. Upon annealing, for samples containing Dy, the formation of C-Ag-C organometallic bonds and concomitant C-C coupling is inhibited, giving rise to a self-assembly of debrominated monomers, showing only a minority number of covalent dimes species. For samples without Dy covalent chains of irregular length are promoted. Our studies open new avenues for using lanthanide elements as efficient dehalogenation catalysts. Furthermore, we illustrate their potential as inhibitors of uncontrolled C-C coupling reactions, of great relevance for fine-tuning the length of polymeric compounds.</p>","","","","","","","","","","","","","2017-05-22","2017-05-22","2017-05-22","","","6","","1","","","","","","false","","","" "1097365","Mikula, M. (Comenius University, Slovakia; Institute Mat and Machine Mech SAS, Slovakia);Sangiovanni, Davide [davsa82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Ruhr University of Bochum, Germany);Plasienka, D. (Comenius University, Slovakia);Roch, T. (Comenius University, Slovakia);Caplovicova, M. (Slovak University of Technology Bratislava, Slovakia);Truchly, M. (Comenius University, Slovakia);Satrapinskyy, L. (Comenius University, Slovakia);Bystricky, R. (Slovak Academic Science, Slovakia);Tonhauzerova, D. (Comenius University, Slovakia);Vlckova, D. (Comenius University, Slovakia);Kus, P. (Comenius University, Slovakia)","Thermally induced age hardening in tough Ta-Al-N coatings via spinodal decomposition","Artikel i tidskrift","Refereegranskat","eng","Journal of Applied Physics","0021-8979","1089-7550","published","121","15","","","","2017","","","","AMER INST PHYSICS","","","","","","","10.1063/1.4981534","000399903200029","","","urn:nbn:se:liu:diva-137606","","","","Bearbetnings-, yt- och fogningsteknik (20505)","","","<p>Funding Agencies|Slovak Research and Development Agency [APVV-14-0173]; Operational Program Research and Development [ITMS 26210120010]; Ministry of Education, Science, Research and Sport of the Slovak Republic within the Research and Development Operational Programme for the project ""University Science Park of STU Bratislava"" [ITMS 26240220084]; European Regional Development Fund; Olle Engkvist Foundation</p>","<p>We combine experiments and ab initio density functional theory calculations to investigate the evolution in structural and mechanical properties of TaAlN coatings as a function of the annealing temperature T. Formation of coherent cubic TaN- and AlN-rich nanometer-size domains, occurring during the initial stage of thermally induced phase separation within cubic NaCl-type (B1) TaAlN solid solutions, yields a monotonic increase in hardness from 29 GPa (as deposited coatings) up to a maximum of 35 GPa (+17%) reached after annealing at 1000 degrees C. Further thermal treatment at T amp;gt; 1000 degrees C leads to the transformation of metastable cubic domains into stable hexagonal TaNx and wurtzite AlN phases, thus resulting in hardness reductions. A comparison of our results with those reported in the literature reveals that TaAlN coatings are at least as hard while considerably less stiff (lower elastic moduli) than TiAlN coatings, thus indicating a substantial increase in toughness achieved upon replacing Ti with Ta in the host lattice. Present findings suggest that cubic TaAlN solid solutions are promising candidates for applications in protective coatings possessing both high-temperature hardness and toughness. Published by AIP Publishing.</p>","","","","","","","","","","","","","2017-05-22","2017-05-22","2017-05-22","","","11","","1","","","","","155304","false","","","" "1098089","Leonov, I. (University of Augsburg, Germany; National University of Science and Technology MISIS, Russia);Greenberg, E. (Tel Aviv University, Israel; University of Chicago, IL USA);Belov, M. P. (National University of Science and Technology MISIS, Russia);Rozenberg, G. Kh. (Tel Aviv University, Israel);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Mott transition and magnetic collapse in iron-bearing compounds under high pressure","Artikel i tidskrift","Refereegranskat","eng","High Pressure Research","0895-7959","1477-2299","published","37","2","","96","118","2017","","","","TAYLOR & FRANCIS LTD","","","","","","","10.1080/08957959.2017.1302445","000399885500002","","","urn:nbn:se:liu:diva-137587","","","Strong correlations; high pressure; Mott metal-insulator transition; spin-state transition; transition metal oxides","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Deutsche Forschungsgemeinschaft through Transregio TRR [80]; Ministry of Education and Science of the Russian Federation [K3-2016-027, 14.Y26.31.0005]; Russian Foundation for Basic Research [16-02-01027]; Swedish Research Council (VR) [2015-04391]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]; Israel Science Foundation [1189/14]</p>","<p>We discuss the electronic, magnetic, and related structural transitions in the iron-based Mott insulators under high pressures relevant to the Earths lower mantle conditions. The paper focuses on the above-mentioned topics based primarily on our theoretical analysis and various experimental studies employing synchrotron X-ray diffraction, Fe-57 Mossbauer spectroscopy, and electrical transport measurements. We review the main theoretical tools employed for the analysis of the properties of materials with strongly interacting electrons and discuss the problems of theoretical description of such systems. In particular, we discuss a state-of-the-art method for calculating the electronic structure of strongly correlated materials, the DFT + DMFT method, which merges standard band-structure techniques (DFT) with dynamical mean-field theory of correlated electrons (DMFT). We employ this method to study the pressure-induced magnetic collapse in Mott insulators, such as wustite (FeO), magnesiowustite (Fe1-xMgx)O (x=0.25 and 0.75) and goethite (FeOOH), and explore the consequences of the magnetic collapse for the electronic structure and phase stability of these materials. We show that the paramagnetic cubic B1-structured FeO and (Fe,Mg)O and distorted orthorhombic (Pnma) FeOOH exhibit upon compression a high-to low-spin (HS-LS) transition, which is accompanied by a simultaneous collapse of local moments. However, the HS-LS transition is found to have different consequences for the electronic properties of these compounds. For FeO and (Fe0.75Mg0.25)O, the transition is found to be accompanied by a Mott insulator-to-metal phase transition. In contrast to that, both (Fe0.25Mg0.75)O and FeOOH remain insulating up to the highest studied pressures, indicating that a Mott insulator to band insulator phase transition takes place. Our combined theoretical and experimental studies indicate a crossover between localized to itinerant moment behavior to accompany magnetic collapse of Fe ions.</p>","","","","","","","","","","","","","2017-05-23","2017-05-23","2017-06-14","","","5","","1","","","","","","false","","","" "1097353","Tellander, Felix (Lund University, Sweden);Berggren, Karl-Fredrik [karbe79] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Spectra, current flow, and wave-function morphology in a model PT-symmetric quantum dot with external interactions","Artikel i tidskrift","Refereegranskat","eng","PHYSICAL REVIEW A","2469-9926","","published","95","4","","","","2017","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevA.95.042115","000399932100001","","","urn:nbn:se:liu:diva-137612","","","","Annan fysik (10399)","","","","<p>In this paper we use numerical simulations to study a two-dimensional (2D) quantum dot (cavity) with two leads for passing currents (electrons, photons, etc.) through the system. By introducing an imaginary potential in each lead the system is made symmetric under parity-time inversion (PT symmetric). This system is experimentally realizable in the form of, e.g., quantum dots in low-dimensional semiconductors, optical and electromagnetic cavities, and other classical wave analogs. The computational model introduced here for studying spectra, exceptional points (EPs), wave-function symmetries and morphology, and current flow includes thousands of interacting states. This supplements previous analytic studies of few interacting states by providing more detail and higher resolution. The Hamiltonian describing the system is non-Hermitian; thus, the eigenvalues are, in general, complex. The structure of the wave functions and probability current densities are studied in detail at and in between EPs. The statistics for EPs is evaluated, and reasons for a gradual dynamical crossover are identified.</p>","","","","","","","","","","","","","2017-05-22","2017-05-22","2017-06-15","http://liu.diva-portal.org/smash/get/diva2:1097353/FULLTEXT02.pdf","","2","","0","","","","","042115","false","","","" "1111759","Nilsson, Johan O. (KTH Royal Institute Technology, Sweden);Leetmaa, Mikael (KTH Royal Institute Technology, Sweden);Vekilova, Olga Yu (KTH Royal Institute Technology, Sweden; Uppsala University, Sweden);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Skorodumova, Natalia V. (KTH Royal Institute Technology, Sweden; Uppsala University, Sweden)","Oxygen diffusion in ceria doped with rare-earth elements","Artikel i tidskrift","Refereegranskat","eng","Physical Chemistry, Chemical Physics - PCCP","1463-9076","1463-9084","published","21","","","13723","13730","2017","","","","ROYAL SOC CHEMISTRY","","","","","","","10.1039/c6cp06460d","000402488300037","28497151","","urn:nbn:se:liu:diva-138469","","","","Teoretisk kemi (10407)","","","<p>Funding Agencies|Swedish Energy Agency (STEM) [35515-1]; Carl Tryggers Foundation [CTS 14: 433]; Swedish Research Council (VR) [2014-5993, 2014-4750]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]; [LM2015070]</p>","<p>We examine the effects of the dopant type and the dopant distribution on the ion diffusion in ceria doped with rare-earth elements (Pr, Nd, Pm, Sm, Eu, and Gd). Diffusion is simulated by means of a Kinetic Monte Carlo method using input transition rates derived from diffusion barriers calculated in the framework of density functional theory (DFT). Based on diffusion simulations, we discuss the characteristics of the dopants in terms of the diffusion barriers, and study oxygen ion trajectories for different dopants and distributions. Our simulations show a trend of increasing ion diffusivity with increasing atomic number for all distributions.</p>","","","","","","","","","","","","","2017-06-19","2017-06-19","2017-06-19","","","5","","2","","","","","","false","","","" "1120974","Shtepliuk, Ivan [ivash69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (NASU, Ukraine);Caffrey, Nuala M. (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Trinity Coll Dublin, Ireland; Trinity Coll Dublin, Ireland);Iakimov, Tihomir [tihia09] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Khranovskyy, Volodymyr [volkh14] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (National University of Science and Technology MISIS, Russia);Yakimova, Rositsa [rosia15] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902])","On the interaction of toxic Heavy Metals (Cd, Hg, Pb) with graphene quantum dots and infinite graphene","Artikel i tidskrift","Refereegranskat","eng","Scientific Reports","2045-2322","2045-2322","published","7","","","","","2017","","","","NATURE PUBLISHING GROUP","","","","","","","10.1038/s41598-017-04339-8","000403840000006","28638144","","urn:nbn:se:liu:diva-139281","","","","Atom- och molekylfysik och optik (10302)","","","<p>Funding Agencies|European Union [696656]; Swedish Research Council (VR) [621-2014-5805]; Angpanneforeningens Forskningsstiftelse [16-541]; Science Foundation Ireland (SFI) under its Starter Investigator Research Grant (SIRG) Programme [15/SIRG/3314]; Swedish Research Council (VR) Marie Sklodowska Curie International Career Grant [2015-00679]; AForsk [14-517]; Swedish Government Strategic Research Areas in Materials Science on Functional Materials at Linkoping University [2009-00971]; Knut and Alice Wallenberg Foundation through the Strong Field Physics and New States of Matter Grant; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]</p>","<p>The promise of graphene and its derivatives as next generation sensors for real-time detection of toxic heavy metals (HM) requires a clear understanding of behavior of these metals on the graphene surface and response of the graphene to adsorption events. Our calculations herein were focused on the investigation of the interaction between three HMs, namely Cd, Hg and Pb, with graphene quantum dots (GQDs). We determine binding energies and heights of both neutral and charged HM ions on these GQDs. The results show that the adsorption energy of donor-like physisorbed neutral Pb atoms is larger than that of either Cd or Hg. In contrast to the donor-like behavior of elemental HMs, the chemisorbed charged HM species act as typical acceptors. The energy barriers to migration of the neutral adatoms on GQDs are also estimated. In addition, we show how the substitution of a carbon atom by a HM adatom changes the geometric structure of GQDs and hence their electronic and vibrational properties. UV-visible absorption spectra of HM-adsorbed GQDs vary with the size and shape of the GQD. Based on our results, we suggest a route towards the development of a graphene-based sensing platform for the optical detection of toxic HMs.</p>","","","","","","","","","","","","","2017-07-07","2017-07-07","2017-08-27","http://liu.diva-portal.org/smash/get/diva2:1120974/FULLTEXT01.pdf","","6","","1","","","","","3934","false","","","" "1151715","Mosyagin, Igor [igomo87] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (NUST MISIS, Russia);Lugovskoy, A. V. (NUST MISIS, Russia);Krasilnikov, O. M. (NUST MISIS, Russia);Vekilov, Yu. Kh. (NUST MISIS, Russia; NUST MISIS, Russia);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Ab initio calculations of pressure-dependence of high-order elastic constants using finite deformations approach","Artikel i tidskrift","Refereegranskat","eng","Computer Physics Communications","0010-4655","1879-2944","published","220","","","20","30","2017","","","","ELSEVIER SCIENCE BV","","","","","","","10.1016/j.cpc.2017.06.008","000412252300002","","","urn:nbn:se:liu:diva-142141","","","Ab initio calculations; Elastic moduli; Pressure effects in solids and liquids","Beräkningsmatematik (10105)","","","<p>Funding Agencies|Swedish Foundation for Strategic Research (SSF) program SRL Grant [10-0026]; Swedish Research Council [2015-04391, 2014-4750]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [SFO-Mat-LiU No 2009 00971]; Ministry of Education and Science of the Russian Federation [K2-2016-013, 211]</p>","<p>We present a description of a technique for ab initio calculations of the pressure dependence of second and third-order elastic constants. The technique is based on an evaluation of the corresponding Lagrangian stress tensor derivative of the total energy assuming finite size of the deformations. Important details and parameters of the calculations are highlighted. Considering body-centered cubic Mo as a model system, we demonstrate that the technique is highly customizable and can be used to investigate non-linear elastic properties under high-pressure conditions. (C) 2017 Elsevier B.V. All rights reserved.</p>","","","","","","","","","","","","","2017-10-24","2017-10-24","2017-10-24","","","6","","1","","","","","","false","","","" "1153679","Cirera, Borja (IMDEA Nanosci, Spain);Trukhina, Olga (University of Autonoma Madrid, Spain);Björk, Jonas [jonbj66] [0000-0002-1345-0006] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Bottari, Giovanni (IMDEA Nanosci, Spain; University of Autonoma Madrid, Spain; University of Autonoma Madrid, Spain);Rodriguez-Fernandez, Jonathan (University of Autonoma Madrid, Spain);Martin-Jimenez, Alberto (IMDEA Nanosci, Spain);Islyaikin, Mikhail K. (Ivanovo State University of Chemistry and Technology, Russia);Otero, Roberto (IMDEA Nanosci, Spain; University of Autonoma Madrid, Spain);Gallego, Jose M. (CSIC, Spain);Miranda, Rodolfo (IMDEA Nanosci, Spain; University of Autonoma Madrid, Spain);Torres, Tomas (IMDEA Nanosci, Spain; University of Autonoma Madrid, Spain; University of Autonoma Madrid, Spain);Ecija, David (IMDEA Nanosci, Spain)","Long-Range Orientational Self-Assembly, Spatially Controlled Deprotonation, and Off-Centered Metalation of an Expanded Porphyrin","Artikel i tidskrift","Refereegranskat","eng","Journal of the American Chemical Society","0002-7863","1520-5126","published","139","40","","14129","14136","2017","","","","AMER CHEMICAL SOC","","","","","","","10.1021/jacs.7b06406","000413057100032","28889740","","urn:nbn:se:liu:diva-142425","","","","Annan kemi (10499)","","","<p>Funding Agencies|Spanish Ministerio de Economia y Competitividad (MINECO) [RYC-2012-11133, FIS 2013-40667-P, CTQ2014-52869-P, FIS 2015-67287-P]; Comunidad de Madrid [S2013/MIT-2841, S2013/MIT-3007]; European Union; Russian Science Foundation [1423-00204-P]</p>","<p>Expanded porphyrins are large-cavity macro cycles with enormous potential in coordination chemistry, anion sensing, photodynamic therapy, and optoelectronics. In the last two decades, the surface science community has assessed the physicochemical properties of tetrapyrrolic-like macrocydes. However, to date, the sublimation, self-assembly and atomistic insights of expanded porphyrins on surfaces have remained elusive. Here, we show the self-assembly on Au(111) of an expanded aza-porphyrin, namely, an ""expanded hemi-spatially-controlled porphyrazine"", through a unique growth mechanism based on deprotonation long-range orientational self-assembly. Furthermore, a spatially controlled ""writing"" protocol on such self-assembled architecture is presented based on the STM tip-induced deprotonation of the inner protons of individual macrocydes. Finally, the capability of these surface-confined macrocydes to host lanthanide elements is assessed, introducing a novel off-centered coordination motif. The presented findings represent a milestone in the fields of porphyrinoid chemistry and surface science, revealing a great potential for novel surface patterning, opening new avenues for molecular level information storage, and boosting the emerging field of surface-confined coordination chemistry involving f-block elements.</p>","","","","","","","","","","","","","2017-10-31","2017-10-31","2017-10-31","","","12","","2","","","","","","false","","","" "1135457","Fashandi, Hossein [hosfa18] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Dahlqvist, Martin [marda09] [0000-0001-5036-2833] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Lu, Jun [junlu07] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Palisaitis, Justinas [juspa01] [0000-0003-3203-7935] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Rosén, Johanna [johro07] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Hultman, Lars [larhu75] [0000-0002-2837-3656] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Andersson, Mike [mikan22] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tillämpad sensorvetenskap [11901]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Lloyd Spetz, Anita [anill63] [0000-0002-2817-3574] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tillämpad sensorvetenskap [11901]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Eklund, Per [perek02] [0000-0003-1785-0864] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Synthesis of Ti3AuC2, Ti3Au2C2 and Ti3IrC2 by noble metal substitution reaction in Ti3SiC2 for high-temperature-stable Ohmic contacts to SiC","Artikel i tidskrift","Refereegranskat","eng","Nature Materials","1476-1122","1476-4660","published","16","8","","814","818","2017","","","","NATURE PUBLISHING GROUP","","","","","","","10.1038/NMAT4896","000406424600012","28459444","","urn:nbn:se:liu:diva-139912","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|VINN Excellence Center in research and innovation on Functional Nanoscale Materials (FunMat) by the Swedish Governmental Agency for Innovation Systems (VINNOVA); Swedish Government Strategic Research Areas in Materials Science on Functional Materials at Linkoping University [2009 00971]; Swedish Foundation for Strategic Research through the Future Research Leaders 5 Program; Synergy Grant FUNCASE, Functional Carbides and Advanced Surface Engineering; e-Science Research Centre (SeRC); Swedish Research Council (VR) [2014-4750]; European Research Council under the European Community [335383]; Knut and Alice Wallenberg Foundation</p>","<p>The large class of layered ceramics encompasses both van der Waals (vdW) and non-vdW solids. While intercalation of noble metals in vdW solids is known, formation of compounds by incorporation of noble-metal layers in non-vdW layered solids is largely unexplored. Here, we show formation of Ti3AuC2 and Ti3Au2C2 phases with up to 31% lattice swelling by a substitutional solid-state reaction of Au into Ti3SiC2 single-crystal thin films with simultaneous out-diffusion of Si. Ti3IrC2 is subsequently produced by a substitution reaction of Ir for Au in Ti3Au2C2. These phases form Ohmic electrical contacts to SiC and remain stable after 1,000 h of ageing at 600 degrees C in air. The present results, by combined analytical electron microscopy and ab initio calculations, open avenues for processing of noble-metal-containing layered ceramics that have not been synthesized from elemental sources, along with tunable properties such as stable electrical contacts for high-temperature power electronics or gas sensors.</p>","","","","","","","","","","","","","2017-08-23","2017-08-23","2017-11-03","http://liu.diva-portal.org/smash/get/diva2:1135457/FULLTEXT01.pdf","","11","","2","","","","","","false","","","" "1078843","Finzel, Kati [katfi97] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","About the compatibility between ansatzes and constraints for a local formulation of orbital-free density functional theory","Artikel i tidskrift","Refereegranskat","eng","International Journal of Quantum Chemistry","0020-7608","1097-461X","published","117","5","","","","2017","","","","WILEY-BLACKWELL","","","","","","","10.1002/qua.25329","000392757200002","","","urn:nbn:se:liu:diva-134796","","","orbital-free density functional theory; one-point functionals; local density approximation; Pauli potential; non-analytical functional","Teoretisk kemi (10407)","","","<p>Funding Agencies|Alexander von Humboldt foundation; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [Faculty Grant SFO Mat LiU No 2009 00971]</p>","<p>Functional properties that are exact for the Hohenberg-Kohn functional may turn into mutually exclusive constraints at a given level of ansatz. This is exemplarily shown for the local density approximation. Nevertheless, it is possible to reach exactly the Kohn-Sham data from an orbital-free density functional framework based on simple one-point functionals by starting from the Levy-Perdew-Sahni formulation. The energy value is obtained from the density-potential pair, and therefore does not refer to the functional dependence of the potential expression. Consequently, the potential expression can be obtained from any suitable model and is not required to follow proper scaling behavior.</p>","","","","","","","","","","","","","2017-03-06","2017-03-06","2017-11-29","","","1","","1","","","","","UNSP e25329","false","","","" "1060905","Brodin, Gert (Umeå University, Sweden);Stenflo, Lennart [lenst65] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Juul Rasmussen, Jens (Technical University of Denmark, Denmark)","Focus issue to honour Hans L Pecseli on his 70th birthday","Artikel i tidskrift","Övrigt vetenskapligt","eng","Physica Scripta","0031-8949","1402-4896","published","92","1","","","","2017","","","","IOP PUBLISHING LTD","","","","","","","10.1088/0031-8949/92/1/010301","000389326000001","","","urn:nbn:se:liu:diva-133500","","","","Fysik (103)","","","","<p>n/a</p>","","","","","","","","","","","","","2016-12-29","2016-12-30","2017-11-29","","","3","","1","","editorialMaterial","","","010301","false","","","" "1060097","Finzel, Kati [katfi97] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Baranov, Alexey I. (Max Planck Institute Chemistry Phys Solids, Germany)","A simple model for the Slater exchange potential and its performance for solids","Artikel i tidskrift","Refereegranskat","eng","International Journal of Quantum Chemistry","0020-7608","1097-461X","published","117","1","","40","47","2017","","","","WILEY-BLACKWELL","","","","","","","10.1002/qua.25312","000388601500006","","","urn:nbn:se:liu:diva-133370","","","band gaps; exchange potential; Slater potential","Teoretisk kemi (10407)","","","<p>Funding Agencies|Alexander von Humboldt foundation; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]; Deutsche Forschungsgemeinschaft [DFG BA-4911/1-1]</p>","<p>A simple local model for the Slater exchange potential is determined by least square fit procedure from Hartree-Fock (HF) atomic data. Since the Slater potential is the exact exchange potential yielding HF electron density from Levy-Perdew-Sahni density functional formalism (Levy et al., Phys. Rev. A 1984, 30, 2745), the derived local potential is significantly more negative than the conventional local density approximation. On the set of 22 ionic, covalent and van der Waals solids including strongly correlated transition metal oxides, it has been demonstrated, that this simple model potential is capable of reproducing the band gaps nearly as good as popular meta GGA potentials in close agreement with experimental values.</p>","","","","","","","","","","","","","2016-12-22","2016-12-27","2017-11-29","","","2","","1","","","","","","false","","","" "1135446","Green, B. L. (University of Warwick, England);Breeze, B. G. (University of Warwick, England);Rees, G. J. (University of Warwick, England);Hanna, J. V. (University of Warwick, England);Chou, J. -P. (Hungarian Academic Science, Hungary);Ivady, Viktor [vikiv58] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Hungarian Academic Science, Hungary);Gali, A. (Hungarian Academic Science, Hungary; Budapest University of Technology and Econ, Hungary);Newton, M. E. (University of Warwick, England)","All-optical hyperpolarization of electron and nuclear spins in diamond","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","96","5","","","","2017","","","College Park","American Physical Society","","","","","","","10.1103/PhysRevB.96.054101","000406671100001","","","urn:nbn:se:liu:diva-139914","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Engineering and Physical Sciences Research Council [EP/M013243/1, EP/J500045/1]; Gemological Institute of America; EU Commission (FP7 DIADEMS Project) [611143]</p>","<p>Low thermal polarization of nuclear spins is a primary sensitivity limitation for nuclear magnetic resonance. Here we demonstrate optically pumped (microwave-free) nuclear spin polarization of C-13 and N-15 in N-15-doped diamond. (15)Npolarization enhancements up to- 2000 above thermal equilibrium are observed in the paramagnetic system Ns(0). Nuclear spin polarization is shown to diffuse to bulk C-13 with NMR enhancements of -200 at room temperature and -500 at 240 K, enabling a route to microwave-free high-sensitivity NMR study of biological samples in ambient conditions.</p>","","","","","","","","","","","","","2017-08-23","2017-08-23","2017-11-29","http://liu.diva-portal.org/smash/get/diva2:1135446/FULLTEXT01.pdf","","8","","0","","","","","054101","true","","","" "1120979","Christle, David J. (University of Chicago, IL 60637 USA);Klimov, Paul V. (University of Chicago, IL 60637 USA);de las Casas, Charles F. (University of Chicago, IL 60637 USA);Szasz, Krisztian (Hungarian Academic Science, Hungary);Ivády, Viktor [vikiv58] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Hungarian Academic Science, Hungary);Jokubavicius, Valdas [valjo12] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Ul-Hassan, Jawad [jawul47] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Syväjärvi, Mikael [miksy08] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Koehl, William F. (University of Chicago, IL 60637 USA);Ohshima, Takeshi (National Institute Quantum and Radiol Science and Technology, Japan);Nguyen, Son Tien [nguso90] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Janzén, Erik [erija14] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Gali, Adam (Hungarian Academic Science, Hungary; Budapest University of Technology and Econ, Hungary);Awschalom, David D. (University of Chicago, IL 60637 USA)","Isolated Spin Qubits in SiC with a High-Fidelity Infrared Spin-to-Photon Interface","Artikel i tidskrift","Refereegranskat","eng","Physical Review X","2160-3308","2160-3308","published","7","2","","","","2017","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevX.7.021046","000404032900001","","","urn:nbn:se:liu:diva-139278","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|ARO [W911NF-15-2-0058]; AFOSR [FA9550-15-1-0029, FA9550-14-1-0231]; NSF MRSEC [DMR-1420709]; DOE LDRD Program; Swedish Research Council [621-2014-5825, 2016-04068]; AForsk foundation [16-576]; Carl-Trygger Stiftelse for Vetenskaplig Forskning [CTS 15:339]; Knut and Alice Wallenberg Foundation [KAW 2013.0300]; JSPS [26286047]; Swedish Energy Agency [43611-1]</p>","<p>The divacancies in SiC are a family of paramagnetic defects that show promise for quantum communication technologies due to their long-lived electron spin coherence and their optical addressability at near-telecom wavelengths. Nonetheless, a high-fidelity spin-photon interface, which is a crucial prerequisite for such technologies, has not yet been demonstrated. Here, we demonstrate that such an interface exists in isolated divacancies in epitaxial films of 3C-SiC and 4H-SiC. Our data show that divacancies in 4H-SiC have minimal undesirable spin mixing, and that the optical linewidths in our current sample are already similar to those of recent remote entanglement demonstrations in other systems. Moreover, we find that 3C-SiC divacancies have a millisecond Hahn-echo spin coherence time, which is among the longest measured in a naturally isotopic solid. The presence of defects with these properties in a commercial semiconductor that can be heteroepitaxially grown as a thin film on Si shows promise for future quantum networks based on SiC defects.</p>","","","","","","","","","","","","","2017-07-07","2017-07-07","2017-11-29","http://liu.diva-portal.org/smash/get/diva2:1120979/FULLTEXT01.pdf","","14","","0","","","","","21046","false","","","" "1120187","Aschebrock, Thilo (University of Bayreuth, Germany);Armiento, Rickard [ricar47] [0000-0002-5571-0814] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Kuemmel, Stephan (University of Bayreuth, Germany)","Orbital nodal surfaces: Topological challenges for density functionals","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","95","24","","","","2017","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.95.245118","000403355300004","","","urn:nbn:se:liu:diva-139184","","","","Teoretisk kemi (10407)","","","<p>Funding Agencies|German-Israeli Foundation for Scientific Research and Development; University of Bayreuth Graduate School; Swedish Research Council (VR) [2016-04810]; Swedish e-Science Research Centre (SeRC)</p>","<p>Nodal surfaces of orbitals, in particular of the highest occupied one, play a special role in Kohn-Sham density-functional theory. The exact Kohn-Sham exchange potential, for example, shows a protruding ridge along such nodal surfaces, leading to the counterintuitive feature of a potential that goes to different asymptotic limits in different directions. We show here that nodal surfaces can heavily affect the potential of semilocal density-functional approximations. For the functional derivatives of the Armiento-Kummel (AK13) [Phys. Rev. Lett. 111, 036402 (2013)] and Becke88 [Phys. Rev. A 38, 3098 (1988)] energy functionals, i.e., the corresponding semilocal exchange potentials, as well as the Becke-Johnson [J. Chem. Phys. 124, 221101 (2006)] and van Leeuwen-Baerends (LB94) [Phys. Rev. A 49, 2421 (1994)] model potentials, we explicitly demonstrate exponential divergences in the vicinity of nodal surfaces. We further point out that many other semilocal potentials have similar features. Such divergences pose a challenge for the convergence of numerical solutions of the Kohn-Sham equations. We prove that for exchange functionals of the generalized gradient approximation (GGA) form, enforcing correct asymptotic behavior of the potential or energy density necessarily leads to irregular behavior on or near orbital nodal surfaces. We formulate constraints on the GGA exchange enhancement factor for avoiding such divergences.</p>","","","","","","","","","","","","","2017-07-05","2017-07-05","2017-11-29","http://liu.diva-portal.org/smash/get/diva2:1120187/FULLTEXT01.pdf","","3","","0","","","","","245118","false","","","" "1089940","Feng, Qingguo [qinfe69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Ekholm, Marcus [marek10] [0000-0002-7563-1494] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Tasnadi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Jönsson, Johan [johjo06] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (NUST MISIS, Russia)","Topological transitions of the Fermi surface of osmium under pressure: an LDA plus DMFT study","Artikel i tidskrift","Refereegranskat","eng","New Journal of Physics","1367-2630","1367-2630","published","19","","","","","2017","","","","IOP PUBLISHING LTD","","","","","","","10.1088/1367-2630/aa5f8e","000398666100004","","","urn:nbn:se:liu:diva-136604","","","electronic topological transitions; strong correlations; Fermi surfaces","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Foundation for Strategic Research SSF (SRL) [10-0026]; Swedish Research Council (VR) grant [2015-04391]; Knut and Alice Wallenberg Foundation [2014-2019]; Swedish Government Strategic Research Area SeRC; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFOMatLiU) [2009 00971]; Ministry of Education and Science of the Russian Federation of NUST MISIS [K2-2016-013]; PHD DALEN Project [26228RM]; Swedish National Infrastructure for Computing (SNIC)</p>","<p>The influence of pressure on the electronic structure of Os has attracted substantial attention recently due to reports on isostructural electronic transitions in this metal. Here, we theoretically investigate the Fermi surface of Os from ambient to high pressure, using density functional theory combined with dynamical mean field theory. Weprovide a detailed discussion of the calculated Fermi surface and its dependence on the level of theory used for the treatment of the electron-electron interactions. Although we confirm that Os can be classified as weakly correlated metal, the inclusion of local quantum fluctuations between 5d electrons beyond the local density approximation explains the most recent experimental reports regarding the occurrence of electronic topological transitions in Os.</p>","","","","","","","","","","","","","2017-04-21","2017-04-21","2017-11-29","http://liu.diva-portal.org/smash/get/diva2:1089940/FULLTEXT01.pdf","","5","","0","","","","","033020","false","","","" "1089979","Sun, Weiwei (Uppsala University, Sweden; KTH Royal Institute Technology, Sweden);Luo, Wei (Uppsala University, Sweden);Feng, Qingguo [qinfe69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Ahuja, Rajeev (Uppsala University, Sweden; KTH Royal Institute Technology, Sweden)","Anisotropic distortion and Lifshitz transition in alpha-Hf under pressure","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","95","11","","","","2017","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.95.115130","000396273400004","","","urn:nbn:se:liu:diva-136595","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Research Council (V.R.); CSC scholarship</p>","<p>In this work we report a theoretical investigation on behavior of the elastic constant C-44 and the transverse optical phonon mode E(2)g of a-Hf under pressure within the density functional theory. In contrast to many other reported transition metals, the above two quantities do not show a synchronous relation as pressure increases. Below 13 GPa, an opposite shifting tendency has been observed. However, once the pressure is raised above 13 GPa, the trend is pulled back to be consistent. This anomalous behavior is figured out to be caused by the large lattice anisotropy of the c/a ratio along with the elastic anisotropy. The synchronous behavior is found to be in accordance with the behavior of c/a ratio with increased pressure. In our band-structure investigations the electronic topological transition has been discovered at 10 GPa, which relates to the change of c/a ratio suggested by recent literature. The presence of the Van Hove singularity shown in the densities of states has been identified and regarded as the origin of the variation of C-44 and E(2)g.</p>","","","","","","","","","","","","","2017-04-21","2017-04-21","2017-11-29","http://liu.diva-portal.org/smash/get/diva2:1089979/FULLTEXT01.pdf","","4","","0","","","","","115130","false","","","" "1087954","Ribeiro, Luiz Antonio [luiri41] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Brasilia, Brazil);Stafström, Sven [svest87] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Polaron dynamics in anisotropic Holstein-Peierls systems","Artikel i tidskrift","Refereegranskat","eng","Physical Chemistry, Chemical Physics - PCCP","1463-9076","1463-9084","published","19","5","","4078","4084","2017","","","","ROYAL SOC CHEMISTRY","","","","","","","10.1039/c6cp07478b","000395328100069","28111670","","urn:nbn:se:liu:diva-136315","","","","Annan fysik (10399)","","","<p>Funding Agencies|Brazilian Research Council FAP-DF [0193.000942/2015]; Brazilian Ministry of Planning, Budget and Management [DIPLA 005/2016]</p>","<p>Polaron dynamics in anisotropic organic molecular semiconductors is theoretically investigated and simulated in the framework of a semi-classical Holstein-Peierls model. Our computational protocol is presented and applied to studies of a two-dimensional molecular crystal. The intermolecular (Peierls) parameters for a particular crystal direction are systematically changed in order to study the effect of anisotropy in the system. The usefulness of this methodology is highlighted by studying the polaron dynamics on a picosecond timescale, which provides a microscopic insight into the influence of the interplay between different intramolecular parameters on the charge transport mechanism. Our results show that the polaron mobility is substantially reduced in going from an anisotropic to an isotropic relationship between the Peierls parameters for different directions in the crystal. Interestingly, the molecular charge distribution presents three different signatures corresponding to a one-dimensional polaron, a two-dimensional polaron, and an intermediate state for which the polaron localization depends on the degree of anisotropy. Importantly, the two-dimensional polaron, which is present in the essentially isotropic system, is immobile whereas the other two types of polarons are mobile. This, in order for polaron transport to occur in a two-dimensional molecular based system, this system has to be anisotropic.</p>","","","","","","","","","","","","","2017-04-10","2017-04-10","2017-11-29","","","2","","2","","","","","","false","","","" "1151695","Golosova, N. O. (Joint Institute Nucl Research, Russia);Kozlenko, D. P. (Joint Institute Nucl Research, Russia);Dubrovinsky, L. S. (University of Bayreuth, Germany);Cerantola, V. (European Synchrotron Radiat Facil, France);Bykov, M. (University of Bayreuth, Germany);Bykova, E. (University of Bayreuth, Germany; DESY, Germany);Kichanov, S. E. (Joint Institute Nucl Research, Russia);Lukin, E. V. (Joint Institute Nucl Research, Russia);Savenko, B. N. (Joint Institute Nucl Research, Russia);Ponomareva, A. V. (National University of Science and Technology MISIS, Russia);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Magnetic and structural properties of FeCO3 at high pressures","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","96","13","","","","2017","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.96.134405","000412054400003","","","urn:nbn:se:liu:diva-142153","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Swedish Research Council [2015-04391]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkping University [2009 00971]</p>","<p>The structural and magnetic properties of siderite FeCO3 have been studied by means of neutron powder diffraction at pressures up to 7.5 GPa and first-principles theoretical calculations. The lattice compression in the rhombohedral calcite-type structure is dominated by the reduction of the Fe-O bonds, while the changes of the C-O bonds are much less pronounced. The Neel temperature of the antiferromagnetic ( AFM) ground state increases substantially under pressure with a coefficient dT(N)/dP = 1.8K/GPa, which is about 1.5 times larger in comparison with those predicted by the empirical Bloch rule. The ab initio calculations were performed in the framework of the density functional theory including Hubbard-U correction. The calculated structural parameters and Neel temperature as functions of pressure provide a reasonable agreement with the experimental results. The analysis of the density of electronic states points toward increased covalent bonding between the Fe and O atoms upon pressure, giving rise to unexpectedly large pressure coefficient of the Neel temperature and reduced ordered magnetic moments of Fe atoms.</p>","","","","","","","","","","","","","2017-10-24","2017-10-24","2017-11-29","http://liu.diva-portal.org/smash/get/diva2:1151695/FULLTEXT01.pdf","","11","","0","","","","","134405","false","","","" "1147321","Gambino, Davide [davga91] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Sangiovanni, Davide [davsa82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Ruhr University of Bochum, Germany);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Max Planck Institute Eisenforsch GmbH, Germany);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (National University of Science and Technology MISIS, Russia)","Nonequilibrium ab initio molecular dynamics determination of Ti monovacancy migration rates in B1 TiN","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","96","10","","","","2017","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.96.104306","000411076000005","","","urn:nbn:se:liu:diva-141712","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Foundation for Strategic Research (SSF) project SRL [10-0026]; Swedish Research Council (VR) [621-2011-4417, 2015-04391, 330-2014-6336]; Swedish Government Strategic Research Area Grant in Materials Science on Advanced Functional Materials [MatLiU 2009-00971]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Marie Sklodowska Curie Actions [INCA 600398]; Swedish Foundation for Strategic Research; Stiftelsen Olle Engkvist Byggmastare</p>","<p>We use the color diffusion (CD) algorithm in nonequilibrium (accelerated) ab initio molecular dynamics simulations to determine Ti monovacancy jump frequencies in NaCl-structure titanium nitride (TiN), at temperatures ranging from 2200 to 3000 K. Our results showthat theCDmethod extended beyond the linear-fitting rate-versus-force regime [Sangiovanni et al., Phys. Rev. B 93, 094305 (2016)] can efficiently determine metal vacancy migration rates in TiN, despite the low mobilities of lattice defects in this type of ceramic compound. We propose a computational method based on gamma-distribution statistics, which provides unambiguous definition of nonequilibrium and equilibrium (extrapolated) vacancy jump rates with corresponding statistical uncertainties. The acceleration-factor achieved in our implementation of nonequilibrium molecular dynamics increases dramatically for decreasing temperatures from 500 for T close to the melting point T-m, up to 33 000 for T approximate to 0.7 T-m</p>","","","","","","","","","","","","","2017-10-05","2017-10-05","2017-11-29","http://liu.diva-portal.org/smash/get/diva2:1147321/FULLTEXT01.pdf","","4","","0","","","","","104306","false","","","" "1142320","Leonov, I. (University of Augsburg, Germany; National University of Science and Technology MISIS, Russia);Ponomareva, A. V. (National University of Science and Technology MISIS, Russia);Nazarov, R. (Lawrence Livermore National Lab, CA 94551 USA);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Pressure-induced spin-state transition of iron in magnesiowustite (Fe,Mg)O","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","96","7","","","","2017","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.96.075136","000407778300001","","","urn:nbn:se:liu:diva-140967","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Deutsche Forschungsgemeinschaft [Transregio TRR 80]; Ministry of Education and Science of the Russian Federation [K3-2016-027]; Russian Foundation for Basic Researches [16-02-00797]; Swedish Research Council (VR) [2015-04391]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]</p>","<p>We present a detailed theoretical study of the electronic, magnetic, and structural properties of magnesiowustite Fe-1 Mg-x(x) O with x in the range between 0 and 0.875 using a fully charge self-consistent implementation of the density functional theory plus dynamical mean-field theory method. In particular, we compute the electronic structure and phase stability of the rocksalt B1-structured (Fe,Mg) O at high pressures relevant for the Earths lower mantle. We find that upon compression paramagnetic (Fe,Mg) O exhibits a spin-state transition of Fe2+ ions from a high-spin to low-spin (HS-LS) state which is accompanied by a collapse of local magnetic moments. The HS-LS transition results in a substantial drop in the lattice volume by about 4%-8%, implying a complex interplay between electronic and lattice degrees of freedom. Our results reveal a strong sensitivity of the calculated transition pressure P-tr. upon addition of Mg. While, for Fe-rich magnesiowustite with Mg x amp;lt; 0.5, Ptr. is about 80 GPa, for Mg x = 0.75 it drops to 52 GPa, i. e., by 35%. This behavior is accompanied by a substantial change in the spin transition range from 50 to 140 GPa in FeO to 30 to 90 GPa for x = 0.75. In addition, the calculated bulk modulus (in the HS state) is found to increase by similar to 12% from 142 GPa in FeO to 159 GPa in (Fe,Mg) O with Mg x = 0.875. We find that the pressure-induced HS-LS transition has different consequences for the electronic properties of the Fe-rich and -poor (Fe,Mg) O. For the Fe-rich (Fe,Mg) O, the transition is found to be accompanied by a Mott insulator to a (semi) metal phase transition. In contrast to that, for x amp;gt; 0.25, (Fe,Mg) O remains insulating up to the highest studied pressures, implying a Mott-insulator to band-insulator phase transition at the HS-LS transformation.</p>","","","","","","","","","","","","","2017-09-19","2017-09-19","2017-11-29","http://liu.diva-portal.org/smash/get/diva2:1142320/FULLTEXT01.pdf","","4","","0","","","","","075136","false","","","" "1140100","Pourovskii, L. V. (University of Paris Saclay, France; Coll France, France; National University of Science and Technology MISIS, Russia);Mravlje, J. (Jozef Stefan Institute, Slovenia);Georges, A. (University of Paris Saclay, France; Coll France, France; University of Geneva, Switzerland);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (National University of Science and Technology MISIS, Russia)","Electron-electron scattering and thermal conductivity of epsilon-iron at Earths core conditions","Artikel i tidskrift","Refereegranskat","eng","New Journal of Physics","1367-2630","1367-2630","published","19","","","","","2017","","","","IOP PUBLISHING LTD","","","","","","","10.1088/1367-2630/aa76c9","000407785200001","","","urn:nbn:se:liu:diva-140525","","","thermal conductivity; electronic correlations; electronic structure calculations; iron; extreme conditions","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|European Research Council [ERC-319286 QMAC]; Slovenian Research Agency (ARRS) [P1-0044]; Swedish Research Council (VR) [2014-4750, 2015-04391]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]</p>","<p>The electronic state and transport properties of hot dense iron are of the utmost importance for the understanding of Earths interior. Combining state-of-the-art density functional and dynamical mean field theories we study the impact of electron correlations on the electrical and thermal resistivity of hexagonal close-packed epsilon-Fe at Earths core conditions and show that the electron-electron scattering in epsilon-Fe exhibit a nearly perfect Fermi-liquid (FL) behavior. Accordingly, the quadratic dependence of the scattering rate, typical of FLs, leads to a modification of the Wiedemann-Franz law and suppresses the thermal conductivity with respect to the electrical one. The consequence is a significant increase of the electron-electron thermal resistivity, which is found to be of comparable magnitude to the electron-phonon one.</p>","","","","","","","","","","","","","2017-09-11","2017-09-11","2017-11-29","http://liu.diva-portal.org/smash/get/diva2:1140100/FULLTEXT01.pdf","","5","","0","","","","","073022","false","","","" "1140139","Aschebrock, Thilo (University of Bayreuth, Germany);Armiento, Rickard [ricar47] [0000-0002-5571-0814] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Kuemmel, Stephan (University of Bayreuth, Germany)","Challenges for semilocal density functionals with asymptotically nonvanishing potentials","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","96","7","","","","2017","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.96.075140","000407993900001","","","urn:nbn:se:liu:diva-140510","","","","Annan fysik (10399)","","","<p>Funding Agencies|German-Israeli Foundation for Scientific Research and Development; University of Bayreuth Graduate School; Swedish Research Council (V.R.) [2016-04810]; Swedish e-Science Research Centre (SeRC)</p>","<p>The Becke-Johnson model potential [A. D. Becke and E. R. Johnson, J. Chem. Phys. 124, 221101 ( 2006)] and the potential of the AK13 functional [R. Armiento and S. Kummel, Phys. Rev. Lett. 111, 036402 ( 2013)] have been shown to mimic features of the exact Kohn-Sham exchange potential, such as step structures that are associated with shell closings and particle-number changes. A key element in the construction of these functionals is that the potential has a limiting value far outside a finite system that is a system-dependent constant rather than zero. We discuss a set of anomalous features in these functionals that are closely connected to the nonvanishing asymptotic potential. The findings constitute a formidable challenge for the future development of semilocal functionals based on the concept of a nonvanishing asymptotic constant.</p>","","","","","","","","","","","","","2017-09-11","2017-09-11","2017-11-29","http://liu.diva-portal.org/smash/get/diva2:1140139/FULLTEXT01.pdf","","3","","0","","","","","075140","false","","","" "1153703","Ivády, Viktor [vikiv58] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Hungarian Academic Science, Hungary);Gali, Adam (Hungarian Academic Science, Hungary; Budapest University of Technology and Econ, Hungary);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (National University of Science and Technology MISIS, Russia)","Hybrid-DFT + V-w method for band structure calculation of semiconducting transition metal compounds: the case of cerium dioxide","Artikel i tidskrift","Refereegranskat","eng","Journal of Physics: Condensed Matter","0953-8984","1361-648X","published","29","45","","","","2017","","","","IOP PUBLISHING LTD","","","","","","","10.1088/1361-648X/aa8b93","000412945900001","28891806","","urn:nbn:se:liu:diva-142418","","","hybrid functional; transition metal oxide; quasi-particle equation; orbital dependent potential correction","Teoretisk kemi (10407)","","","<p>Funding Agencies|Knut and Alice Wallenberg Foundation; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Hungarian Academy of Sciences</p>","<p>Hybrid functionals non-local exchange-correlation potential contains a derivative discontinuity that improves on standard semi-local density functional theory (DFT) band gaps. Moreover, by careful parameterization, hybrid functionals can provide self-interaction reduced description of selected states. On the other hand, the uniform description of all the electronic states of a given system is a known drawback of these functionals that causes varying accuracy in the description of states with different degrees of localization. This limitation can be remedied by the orbital dependent exact exchange extension of hybrid functionals; the hybrid-DFT + V-w method (Ivady et al 2014 Phys. Rev. B 90 035146). Based on the analogy of quasi-particle equations and hybrid-DFT single particle equations, here we demonstrate that parameters of hybrid-DFT + V-w functional can be determined from approximate theoretical quasi-particle spectra without any fitting to experiment. The proposed method is illustrated on the charge self-consistent electronic structure calculation for cerium dioxide where itinerant valence states interact with well-localized 4f atomic like states, making this system challenging for conventional methods, either hybrid-DFT or LDA + U, and therefore allowing for a demonstration of the advantages of the proposed scheme.</p>","","","","","","","","","","","","","2017-10-31","2017-10-31","2017-12-01","","","3","","1","","","","","454002","false","","","" "1160463","Kerdsongpanya, Sit [sitke04] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Rensselaer Polytech Institute, NY 12180 USA);Hellman, Olle [olohe96] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (CALTECH, CA 91125 USA);Sun, Bo (National University of Singapore, Singapore);Kan Koh, Yee (National University of Singapore, Singapore);Lu, Jun [junlu07] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Van Nong, Ngo (Department of Energy Conversion and Storage, Technical University of Denmark, Risø Campus, Roskilde, Denmark);Simak, Sergei I. [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Max Planck Institute Eisenforsch GmbH, Germany);Eklund, Per [perek02] [0000-0003-1785-0864] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Phonon thermal conductivity of scandium nitride for thermoelectrics from first-principles calculations and thin-film growth","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","96","19","","","","2017","","","","American Physical Society","","","","","","","10.1103/PhysRevB.96.195417","000414738200008","","","urn:nbn:se:liu:diva-143238","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|European Research Council under the European Communitys Seventh Framework Programme [FP/2007-2013]; ERC [335383]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]; Swedish Research Council [2012-4430, 2016-03365, 330-2014-6336, 2014-4750, 637-2013-7296]; Linnaeus Environment LiLi-NFM; Swedish Foundation for Strategic Research (SSF) through the Future Research Leaders 5 Program; NanoCaTe project (FP7) [604647]; National University of Singapore Startup Grant</p>","<p>The knowledge of lattice thermal conductivity of materials under realistic conditions is vitally important since many modern technologies require either high or low thermal conductivity. Here, we propose a theoretical model for determining lattice thermal conductivity, which takes into account the effect of microstructure. It is based on ab initio description that includes the temperature dependence of the interatomic force constants and treats anharmonic lattice vibrations. We choose ScN as a model system, comparing the computational predictions to the experimental data by time-domain thermoreflectance. Our experimental results show a trend of reduction in lattice thermal conductivity with decreasing domain size predicted by the theoretical model. These results suggest a possibility to control thermal conductivity by microstructural tailoring and provide a predictive tool for the effect of the microstructure on the lattice thermal conductivity of materials based on ab initio calculations.</p>","","","","","","","","","","","","","2017-11-27","2017-11-27","2017-12-05","http://liu.diva-portal.org/smash/get/diva2:1160463/FULLTEXT01.pdf","","9","","2","","","","","195417","true","","","" "1162789","Mikula, Marian (Comenius University, Slovakia; Slovak Academic Science, Slovakia);Truchly, Martin (Comenius University, Slovakia);Sangiovanni, Davide [davsa82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Ruhr University of Bochum, Germany);Plasienka, Dusan (Comenius University, Slovakia);Roch, Tomas (Comenius University, Slovakia);Gregor, Maros (Comenius University, Slovakia);Durina, Pavol (Comenius University, Slovakia);Janik, Marian (Comenius University, Slovakia);Kus, Peter (Comenius University, Slovakia)","Experimental and computational studies on toughness enhancement in Ti-Al-Ta-N quaternaries","Artikel i tidskrift","Refereegranskat","eng","Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films","0734-2101","1520-8559","published","35","6","","","","2017","","","","A V S AMER INST PHYSICS","","","","","","","10.1116/1.4997431","000415685300002","","","urn:nbn:se:liu:diva-143366","","","","Oorganisk kemi (10404)","","","<p>Funding Agencies|Slovak Research and Development Agency [APVV-14-0173]; Operational Program Research and Development [ITMS 26210120010]; Olle Engkvist Foundation</p>","<p>Design of hard ceramic material coatings with enhanced toughness, which prevents crack formation/propagation leading to brittle failure during application, is a primary industrial requirement. In this work, experimental methods supported by ab initio density functional theory (DFT) calculations and electronic structure analyses are used to investigate the mechanical behavior of magnetron sputtered Ti-Al-Ta-N hard coatings. The as-deposited Ti1-x-yAlxTayN (y = 0-0.60) films exhibit a single phase cubic sodium chloride (B1) structure identified as TiAl(Ta)N solid solutions. While the hardness H of Ti0.46Al0.54N (32.5 +/- 2 GPa) is not significantly affected by alloying with TaN (H of the quaternary nitrides varies between 26 +/- 2 and 35 +/- 4 GPa), the elastic stiffness monotonically decreases from 442 to 354 GPa with increasing Ta contents, which indicates improved toughness in TiAlTaN. Consistent with the experimental findings, the DFT results show that Ta substitutions in TiAlN reduce the shear resistance due to the enhanced occupation of metal-metal bonding states while preserving strong metal-N bonds. The metal-N bonding character, however, is progressively modified from prevalently ionic (TiAlN) toward more covalent (TiAlTaN). (C) 2017 American Vacuum Society.</p>","","","","","","","","","","","","","2017-12-05","2017-12-05","2017-12-05","","","9","","1","","","","","060602","false","","","" "1159452","Lin, Tao (Technical University of Munich, Germany);Zhang, Liding (Technical University of Munich, Germany);Björk, Jonas [jonbj66] [0000-0002-1345-0006] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Chen, Zhi (Karlsruhe Institute Technology, Germany);Ruben, Mario (Karlsruhe Institute Technology, Germany; University of Strasbourg, France);Barth, Johannes V. (Technical University of Munich, Germany);Klappenberger, Florian (Technical University of Munich, Germany)","Terminal Alkyne Coupling on a Corrugated Noble Metal Surface: From Controlled Precursor Alignment to Selective Reactions","Artikel i tidskrift","Refereegranskat","eng","Chemistry - A European Journal","0947-6539","1521-3765","published","23","62","","15588","15593","2017","","","","WILEY-V C H VERLAG GMBH","","","","","","","10.1002/chem.201701735","000414633200005","28886239","","urn:nbn:se:liu:diva-143071","","","corrugated surface; covalent coupling; scanning tunneling microscopy; surface chemistry; terminal alkyne","Annan kemi (10499)","","","<p>Funding Agencies|DFG priority program 1459; European Union via ERC Advanced Grant MolArt [247299]; China Scholarship Council; IMPRS-APS; TUM University Foundation</p>","<p>Surface-templated covalent coupling of organic precursors currently emerges as a promising route to the atom-precise fabrication of low-dimensional carbon materials. Here, we investigate the adsorption and the coupling reactions of 4,4-diethynyl-1,1:4,1-terphenyl on Au(110) under ultra-high vacuum conditions by using scanning tunneling microscopy combined with density functional theory and kinetic Monte Carlo calculations. Temperature treatment induces both 1,2,4-asymmetric cyclotrimerization and homocoupling, resulting in various reaction products, including a previously unreported, surface-templated H-shaped pentamer. Our analysis of the temperature-dependent relative product abundances unravels that 1,2,4-trimerization and homocoupling proceed via identical intermediate species with the final products depending on the competition of coupling to a third monomer versus dehydrogenation. Our study sheds light on the control of coupling reactions by corrugated surfaces and annealing protocols.</p>","","","","","","","","","","","","","2017-11-22","2017-11-22","2017-12-06","","","7","","2","","","","","","false","","","" "1166701","Lind, Hans [hanli61] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Halim, Joseph [josha78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Rosén, Johanna [johro07] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Investigation of vacancy-ordered Mo1.33C MXene from first principles and x-ray photoelectron spectroscopy","Artikel i tidskrift","Refereegranskat","eng","PHYSICAL REVIEW MATERIALS","2475-9953","","published","1","4","","","","2017","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevMaterials.1.044002","000416576300003","","","urn:nbn:se:liu:diva-143742","","","","Oorganisk kemi (10404)","","","<p>Funding Agencies|Swedish Research Council (VR) [642-2013-8020, 2014-4750]; Knut and Alice Wallenberg (KAW) Foundation [KAW 2015.0043]; SSF synergy grant FUNCASE; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]</p>","<p>MXenes are a comparatively young class of 2D materials, composed of transition-metal carbides/nitrides of the general formula Mn+1XnTx, where T represents surface terminations, typically O, OH, and/or F. Recently, a new type of MXene with vacancy ordering was discovered, Mo1.33CTx, with conduction and capacitance superior to the MXene counterpart without vacancies, Mo2CTx. We here present a theoretical evaluation of Mo1.33CTx based on first-principles calculations, where x = 2 and T is O, F, OH, or a mixture thereof. In addition to structural evaluation upon vacancy formation, we identify preferred terminations as well as termination sites, and resulting dynamical stability and electronic properties. For mixed terminations, the mixing energy is evaluated. We show that while Mo2C is typically O terminated, mixed terminations with a high F content are suggested for Mo1.33CTx, which in turn gives the highest metallicity out of all the configurations investigated. In addition, the results indicate a strong tuning potential of the band gap through choice of terminations, with an electronic structure changing between insulating and metallic depending on termination(s) and their configuration. We also performed x-ray photoelectron spectroscopy to identify and quantify the terminating species on the MXene, as well as their respective binding energies. The experimental results are consistent with the theoretical analysis, and combined they suggest an explanation to the MXene chemistry as well as the reported high conductivity of Mo1.33CTx.</p>","","","","","","","","","","","","","2017-12-15","2017-12-15","2017-12-15","","","4","","0","","","","","044002","false","","","" "1166718","Zheng, Qiye (University of Illinois, USA);Mei, Antonio B. (University of Illinois, USA);Tuteja, Mohit (University of Illinois, USA);Sangiovanni, Davide [davsa82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Ruhr University of Bochum, Germany);Hultman, Lars [larhu75] [0000-0002-2837-3656] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Petrov, Ivan [ivape26] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Illinois, USA);Greene, Joseph E [josgr17] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Illinois, USA);Cahill, David G. (University of Illinois, IL 61801 USA)","Phonon and electron contributions to the thermal conductivity of VNx epitaxial layers","Artikel i tidskrift","Refereegranskat","eng","PHYSICAL REVIEW MATERIALS","2475-9953","","published","1","6","","","","2017","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevMaterials.1.065002","000416597100002","","","urn:nbn:se:liu:diva-143732","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Research Council (VR) [2009-00971, 2013-4018, 2014-5790]; Swedish Government Strategic Research Area Grant in Materials Science (SFO Mat-LiU) on Advanced Functional Materials; Olle Engkvist Foundation</p>","<p>Thermal conductivities of VNx/MgO(001) (0.76 amp;lt;= x amp;lt;= 1.00) epitaxial layers, grown by reactive magnetron sputter deposition, are measured in the temperature range 300 amp;lt; T amp;lt; 1000 K using time-domain thermore-flectance (TDTR). Data for the total thermal conductivity are compared to the electronic contribution to the thermal conductivity calculated from the measured electrical conductivity, the Wiedemann-Franz law, and an estimate of the temperature dependence of the Lorenz number L(T). The total thermal conductivity is dominated by electron contribution and varies between 13 W m(-1) K-1 at x = 0.76 and 20 W m(-1) K-1 at x = 1.00 for T = 300 K and between 25 and 35 W m(-1) K-1 for T = 1000 K. The lattice thermal conductivity vs x ranges from 5 to 7 W m(-1) K-1 at 300 K and decreases by 20% at 500 K. The low magnitude and weak temperature dependence of the lattice thermal conductivity are attributed to strong electron-phonon coupling in VN.</p>","","","","","","","","","","","","","2017-12-15","2017-12-15","2017-12-15","","","8","","0","","","","","065002","false","","","" "1172315","Marcus, Carina [carma08] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Saab AB, SE-58188 Linkoping, Sweden);Andersson, Kent (Swedish Def University, Sweden; National Def University, Finland);Åkerlind, Christina [chrak35] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Swedish Def Research Agency, Sweden)","Balancing the radar and long wavelength infrared signature properties in concept analysis of combat aircraft - A proof of concept","Artikel i tidskrift","Refereegranskat","eng","Aerospace Science and Technology","1270-9638","1626-3219","published","71","","","733","741","2017","","","","ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER","","","","","","","10.1016/j.ast.2017.10.022","000418313700067","","","urn:nbn:se:liu:diva-144148","","","Radar; Infrared; Signatures; Scenario; Evaluation","Rymd- och flygteknik (20302)","","","<p>Funding Agencies|Saab Aeronautics; Swedish Defence University; Swedish Armed Forces</p>","<p>Designing combat aircraft with high military effectiveness, affordability and military suitability requires balancing the efforts of many engineering disciplines during all phases of the development. One particular challenge is aircraft survivability, the aircrafts ability to avoid or withstand hostile actions. Signature management is one way of increasing the survivability by improving the ability to avoid detection. Here, the long-wave infrared and radar signatures are studied simultaneously in a mission context. By establishing a system of systems approach at mission system level, the risk of sub optimization at a technical level is greatly reduced. A relevant scenario is presented where the aim is to incapacitate an air-defense system using three different tactics: A low-altitude cruise missile option, a low and medium altitude combat aircraft option. The technical sub-models, i.e. the properties of the signatures, the weapons and the sensors are modeled to a level suitable for early concept development. The results from the scenario simulations are useful for a relative comparison of properties. Depending on the situation, first detection is made by either radar or infrared sensors. Although the modeling is basic, the complexity of the infrared signature and detection chain is demonstrated and possible pivot points for the balancing of radar and IR signature requirements are identified. The evaluation methodology can be used for qualitative evaluation of aircraft concepts at different design phases, provided that the technical models are adapted to a suitable level of detail. (C) 2017 Elsevier Masson SAS. All rights reserved.</p>","","","","","","","","","","","","","2018-01-09","2018-01-09","2018-01-09","","","3","","1","","","","","","false","","","" "1172200","Wretborn, Joel (DreamWorks Animation, Glendale, USA);Armiento, Rickard [ricar47] [0000-0002-5571-0814] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Museth, Ken (DreamWorks Animation, Glendale, USA)","Animation of crack propagation by means of an extended multi-body solver for the material point method","Artikel i tidskrift","Refereegranskat","eng","Computers & graphics","0097-8493","1873-7684","published","69","","","131","139","2017","","","","Elsevier","","","","","","","10.1016/j.cag.2017.10.005","000418980500014","","","urn:nbn:se:liu:diva-144188","","","Contact; Cracks; Material point method","Annan fysik (10399)","","","","<p>We propose a multi-body solver that extends the Material Point Method (MPM) to simulate cracks in computer animation. We define cracks as the intersection between pieces of bodies created by a pre-fracture process and held together by massless particle constraints (glue particles). These pieces are simulated using a MPM multi-body solver extended by us to efficiently handle N-body collisions. Benefits of the present work include (1) low computational overhead compared to a normal MPM algorithm; (2) good scaling in three dimensions due to our use of sparse grids for background computations; (3) allowing for an easy and controllable setup phase to simulate a desired material failure mode, which is especially useful for computer animation. </p>","","","","","","","","","","","","","2018-01-09","2018-01-09","2018-01-22","http://liu.diva-portal.org/smash/get/diva2:1172200/FULLTEXT01.pdf","","3","","2","","","","","","false","","","" "1156554","Ivády, Viktor [vikiv58] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Hungarian Academic Science, Hungary);Davidsson, Joel [joeda01] [0000-0002-5349-3318] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Nguyen, Tien Son [nguso90] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Ohshima, Takeshi (National Institute Quantum and Radiol Science and Technology, Japan);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (National University of Science and Technology MISIS, Russia);Gali, Adam (Hungarian Academic Science, Hungary; Budapest University of Technology and Econ, Hungary)","Identification of Si-vacancy related room-temperature qubits in 4H silicon carbide","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","96","16","","","","2017","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.96.161114","000413848300001","","","urn:nbn:se:liu:diva-142978","","","","Annan fysik (10399)","","","<p>Funding Agencies|Knut &amp; Alice Wallenberg Foundation project Strong Field Physics and New States of Matter; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Swedish Research Council [VR 2016-04068]; Carl-Trygger Stiftelse for Vetenskaplig Forskning [CTS 15:339]; JSPS KAKENHI [A 17H01056]; Hungarian NKFIH Grant [NVKP_16-1-2016-0152958]</p>","<p>The identification of a microscopic configuration of point defects acting as quantum bits is a key step in the advance of quantum information processing and sensing. Among the numerous candidates, silicon-vacancy related centers in silicon carbide (SiC) have shown remarkable properties owing to their particular spin-3/2 ground and excited states. Although, these centers were observed decades ago, two competing models, the isolated negatively charged silicon vacancy and the complex of negatively charged silicon vacancy and neutral carbon vacancy [Phys. Rev. Lett. 115, 247602 (2015)], are still argued as an origin. By means of high-precision first-principles calculations and high-resolution electron spin resonance measurements, we here unambiguously identify the Si-vacancy related qubits in hexagonal SiC as isolated negatively charged silicon vacancies. Moreover, we identify the Si-vacancy qubit configurations that provide room-temperature optical readout.</p>","","","","","","","","","","","","","2017-11-13","2017-11-13","2018-01-25","http://liu.diva-portal.org/smash/get/diva2:1156554/FULLTEXT01.pdf","","6","","2","","","","","161114","true","","","" "1170027","Wang, Xiao-Ye (Max Planck Institute Polymer Research, Germany);Richter, Marcus (Technical University of Dresden, Germany);He, Yuanqin (Technical University of Munich, Germany);Björk, Jonas [jonbj66] [0000-0002-1345-0006] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Riss, Alexander (Technical University of Munich, Germany);Rajesh, Raju (Max Planck Institute Polymer Research, Germany);Garnica, Manuela (Technical University of Munich, Germany);Hennersdorf, Felix (Technical University of Dresden, Germany);Weigand, Jan J. (Technical University of Dresden, Germany);Narita, Akimitsu (Max Planck Institute Polymer Research, Germany);Berger, Reinhard (Technical University of Dresden, Germany);Feng, Xinliang (Technical University of Dresden, Germany);Auwaerter, Willi (Technical University of Munich, Germany);Barth, Johannes V. (Technical University of Munich, Germany);Palma, Carlos-Andres (Technical University of Munich, Germany);Muellen, Klaus (Max Planck Institute Polymer Research, Germany)","Exploration of pyrazine-embedded antiaromatic polycyclic hydrocarbons generated by solution and on-surface azomethine ylide homocoupling","Artikel i tidskrift","Refereegranskat","eng","Nature Communications","2041-1723","2041-1723","published","8","","","","","2017","","","","NATURE PUBLISHING GROUP","","","","","","","10.1038/s41467-017-01934-1","000417055000002","29208962","","urn:nbn:se:liu:diva-143912","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|European Unions Horizon research and innovation program 2D ink [664878]; Alexander von Humboldt Foundation; European Social Fund; Federal State of Saxony (ESF-Project ""GRAPHD""); H-MSCA-IF program; DFG; ERC Consolidator Grant NanoSurfs [615233]; Max Planck Society; German Excellence Initiative ""Center for Advancing Electronics Dresden"" (cfaed); Graphene Flagship</p>","<p>Nanographenes, namely polycyclic aromatic hydrocarbons (PAHs) with nanoscale dimensions (amp;gt;1 nm), are atomically precise cutouts from graphene. They represent prime models to enhance the scope of chemical and physical properties of graphene through structural modulation and functionalization. Defined nitrogen doping in nanographenes is particularly attractive due to its potential for increasing the number of p-electrons, with the possibility of introducing localized antiaromatic ring elements. Herein we present azomethine ylide homocoupling as a strategy to afford internally nitrogen-doped, non-planar PAH in solution and planar nanographene on surfaces, with central pyrazine rings. Localized antiaromaticity of the central ring is indicated by optical absorption spectroscopy in conjunction with theoretical calculations. Our strategy opens up methods for chemically tailoring graphene and nanographenes, modified by antiaromatic dopants.</p>","","","","","","","","","","","","","2018-01-02","2018-01-02","2018-01-26","http://liu.diva-portal.org/smash/get/diva2:1170027/FULLTEXT01.pdf","","16","","2","","","","","1948","false","","","" "1173632","Belicev, P. P. (University of Belgrade, Serbia);Gligoric, G. (University of Belgrade, Serbia);Maluckov, A. (University of Belgrade, Serbia);Stepic, M. (University of Belgrade, Serbia);Johansson, Magnus [magjo23] [0000-0001-6708-1560] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Localized gap modes in nonlinear dimerized Lieb lattices","Artikel i tidskrift","Refereegranskat","eng","Physical Review A: covering atomic, molecular, and optical physics and quantum information","2469-9926","2469-9934","published","96","6","","","","2017","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevA.96.063838","000418794800006","","","urn:nbn:se:liu:diva-144260","","","","Annan fysik (10399)","","","<p>Funding Agencies|Swedish Research Council [348-2013-6752]; Ministry of Education, Science and Technological Development of the Republic of Serbia [III 45010]</p>","<p>Compact localized modes of ring type exist in many two-dimensional lattices with a flat linear band, such as the Lieb lattice. The uniform Lieb lattice is gapless, but gaps surrounding the flat band can be induced by various types of bond alternations (dimerizations) without destroying the compact linear eigenmodes. Here, we investigate the conditions under which such diffractionless modes can be formed and propagated also in the presence of a cubic on-site (Kerr) nonlinearity. For the simplest type of dimerization with a three-site unit cell, nonlinearity destroys the exact compactness, but strongly localized modes with frequencies inside the gap are still found to propagate stably for certain regimes of system parameters. By contrast, introducing a dimerization with a 12-site unit cell, compact (diffractionless) gap modes are found to exist as exact nonlinear solutions in continuation of flat band linear eigenmodes. These modes appear to be generally weakly unstable, but dynamical simulations show parameter regimes where localization would persist for propagation lengths much larger than the size of typical experimental waveguide array configurations. Our findings represent an attempt to realize conditions for full control of light propagation in photonic environments.</p>","","","","","","","","","","","","","2018-01-12","2018-01-12","2018-01-31","http://liu.diva-portal.org/smash/get/diva2:1173632/FULLTEXT01.pdf","","5","","1","","","","","063838","false","","","" "1173620","Brodin, G. (Umeå University, Sweden);Stenflo, Lennart [lenst65] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Nonlinear dynamics of a cold collisional electron plasma","Artikel i tidskrift","Refereegranskat","eng","Physics of Plasmas","1070-664X","1089-7674","published","24","12","","","","2017","","","","AMER INST PHYSICS","","","","","","","10.1063/1.5011299","000418957200104","","","urn:nbn:se:liu:diva-144270","","","","Fusion, plasma och rymdfysik (10303)","","","","<p>We study the influence of collisions on the dynamics of a cold non-relativistic plasma. It is shown that even a comparatively small collision frequency can significantly change the large amplitude wave solution. Published by AIP Publishing.</p>","","","","","","","","","","","","","2018-01-12","2018-01-12","2018-02-01","","","2","","1","","","","","124505","false","","","" "1092107","Wang, Fei [feiwa67] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Saarland, Germany);Holec, David (University of Leoben, Austria);Odén, Magnus [magod41] [0000-0002-2286-5588] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Muecklich, Frank (University of Saarland, Germany);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (NUST MISIS, Russia);Tasnadi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Systematic ab initio investigation of the elastic modulus in quaternary transition metal nitride alloys and their coherent multilayers","Artikel i tidskrift","Refereegranskat","eng","Acta Materialia","1359-6454","1873-2453","published","127","","","124","132","2017","","","","PERGAMON-ELSEVIER SCIENCE LTD","","","","","","","10.1016/j.actamat.2017.01.017","000397362600012","","","urn:nbn:se:liu:diva-136865","","","Ab initio calculations; Elastic properties; Transition metal nitride alloys; Multicomponent; Multilayers","Annan materialteknik (20599)","","","<p>Funding Agencies|Swedish Foundation for Strategic Research (SSF) project SRL Grant [10-0026]; MERA.NET [2013-02355]; Erasmus Mundus Joint European Doctoral Programme DocMASE; Swedish Research Council (VR) [2015-04391]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]; Grant of Ministry of Education and Science of the Russian Federation [14.Y26.31.000]</p>","<p>We give a comprehensive overview of the elastic properties of cubic quaternary transition metal nitride alloys and coherent nitride multilayers for design of wear resistant hard coatings. The elastic stiffness constants of the alloys are calculated using the special quasirandom structure method. For multilayers with sharp interfaces we prove the applicability of a linear-elasticity approximation and show that it can be used with success instead of performing direct computationally demanding ab initio calculations. We explore the trends and the potential of multicomponent alloying in engineering the strength and ductility of both, quaternary alloys and their multilayers. We investigate X(i-x-y)TixAlyN alloys where Xis Zr, Hf, V, Nb or Ta, and present an analysis based on increasing x. We show that with increasing Ti content ductility can increase in each alloy. Elastic isotropy is observed only in (Zr,Hf,V)((i-x-y))TixAlyN alloys in the middle of the compositional triangle, otherwise a high Youngs modulus is observed along [001]. We predict that coherent TiN/X(1-x-y)TixAlyN and ZrN/X(i-x-3)TixAlyN alloy multilayers with the [111] interfacial direction show increasing ductility with increasing x, while the multilayers with the [001] orientation become more brittle. We show that the Youngs moduli variation in the parent bulk quaternary nitride alloy provide a reliable descriptor to screen the Youngs modulus of coherent multilayers in high-throughput calculations. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.</p>","","","","","","","","","","","","","2017-04-30","2017-04-30","2018-02-09","","","6","","2","urn:nbn:se:liu:diva-145091","","","","","false","","","" "1115939","Tal, Alexey [aleta94] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (National University of Science and Technology MISIS, Russia);Olovsson, Weine [weiol14] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Origin of the core-level binding energy shifts in Au nanoclusters","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","95","24","","","","2017","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.95.245402","000402654300006","","","urn:nbn:se:liu:diva-138891","","","","Teoretisk kemi (10407)","","","<p>Funding Agencies|Knut and Alice Wallenberg Foundation [2012.0083]; Strong Field Physics and New States of Matter (COTXS); Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]</p>","<p>We investigate the shifts of the core-level binding energies in small gold nanoclusters by using ab initio density-functional-theory calculations. The shift of the 4f states is calculated for magic-number nanoclusters in a wide range of sizes and morphologies. We find a nonmonotonous behavior of the core-level shift in nanoclusters depending on the size. We demonstrate that there are three main contributions to the Au 4f shifts, which depend sensitively on the interatomic distances, coordination, and quantum confinement. They are identified and explained by the change of the on-site electrostatic potential.</p>","","","","","","","","","","","","","2017-06-27","2017-06-27","2018-03-15","http://liu.diva-portal.org/smash/get/diva2:1115939/FULLTEXT01.pdf","","3","","0","urn:nbn:se:liu:diva-145684","","","","245402","false","","","" "1140967","Yalamanchili, K. (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Wang, Fei [feiwa67] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Saarland University, Germany);Schramm, Isabella [isaci13] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Saarland University, Germany);Andersson, J. M. (Seco Tools AB, Sweden);Johansson Jöesaar, Mats P. [matjo02] [0000-0003-4577-0976] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Seco Tools AB, Sweden);Tasnadi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Muecklich, F. (Saarland University, Germany);Ghafoor, Naureen [naugh16] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Odén, Magnus [magod41] [0000-0002-2286-5588] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Exploring the high entropy alloy concept in (AlTiVNbCr)N","Artikel i tidskrift","Refereegranskat","eng","Thin Solid Films","0040-6090","1879-2731","published","636","","","346","352","2017","","","","Elsevier","","","","","","","10.1016/j.tsf.2017.06.029","000408037800050","","2-s2.0-85021320078","urn:nbn:se:liu:diva-140796","","","High entropy alloy; Transition metal-Al-N alloys; Atom probe tomography; Ab-initio calculations","Oorganisk kemi (10404)","","","<p>Funding Agencies|Swedish Research Council (VR) [621-2012-4401]; Swedish Foundation for Strategic Research (SSF) through the program MultiFilms [RMA08-0069]; Swedish Government strategic research area grant in material science AFM - SFO MatLiU [2009-00971]; EUs Erasmus Mundus Graduate School in Material Science and Engineering (DocMASE); Swedish Governmental Agency for Innovation Systems (Vinnova) [VINNMer 2011-03464, M-Era.net 2013-02355]; EU [C/4-EFRE-13/2009/Br]; DFG; Federal State Government of Saarland [INST 256/298-1 FUGG]</p>","<p>We have explored the high entropy alloy (HEA) concept in the AlTiVNbCr-nitride material system. (AlTiVNbCr)N coatings synthesized by reactive cathodic arc deposition are close to an ideal cubic solid solution with a positive mean-field enthalpy of mixing of 0.06 eV/atom. First principle calculations showa higher thermodynamic stability for the solid solution relative to their binaries thereby indicating a possible entropy stabilization at a temperature above 727 degrees C. However, the elevated temperature annealing experiments show that the solid solution decomposes to w-AlN and c-(TiVNbCr)N. The limited thermal stability of the solid solution is investigated in relation to several thermodynamic parameters. We suggest that the HEA designed multiprincipal element (AlTiVNbCr) N solid solutions are in a metastable state. (C) 2017 Published by Elsevier B.V.</p>","","","","","","","","","","","","","2017-09-13","2017-09-13","2018-03-27","","","9","","1","","","","","","true","","","" "1111723","Landälv, Ludvig [ludla97] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Sandvik Coromant AB, Sweden);Lu, Jun [junlu07] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Spitz, S. (Karlsruhe Institute Technology, Germany);Leiste, H. (Karlsruhe Institute Technology, Germany);Ulrich, S. (Karlsruhe Institute Technology, Germany);Johansson-Jöesaar, Mats P [matjo02] [0000-0003-4577-0976] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (SECO Tools AB, Sweden);Ahlgren, M. (Sandvik Coromant AB, Sweden);Gothelid, E. (Sandvik Coromant AB, Sweden);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Max Planck Institute Eisenforsch GmbH, Germany);Hultman, Lars [larhu75] [0000-0002-2837-3656] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Stueber, M. (Karlsruhe Institute Technology, Germany);Eklund, Per [perek02] [0000-0003-1785-0864] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Structural evolution in reactive RF magnetron sputtered (Cr,Zr)(2)O-3 coatings during annealing","Artikel i tidskrift","Refereegranskat","eng","Acta Materialia","1359-6454","1873-2453","published","131","","","543","552","2017","","","","PERGAMON-ELSEVIER SCIENCE LTD","","","","","","","10.1016/j.actamat.2017.03.063","000402343400051","","","urn:nbn:se:liu:diva-138476","","","Chromium zirconium oxide; Eskolaite; RF magnetron sputtering; Annealing; TEM","Materialkemi (10403)","","","<p>Funding Agencies|Swedish Research Council (VR) [621-212-4368, 330-2014-6336]; AB Sandvik Coromant; Karlsruhe Nano Micro Facility (KNMF); Helmholtz research infrastructure at Karlsruhe Institute of Technology (KIT); Marie Sklodowska Curie Actions, Cofund [INCA 600398]; Knut and Alice Wallenberg Foundation</p>","<p>Reactive RF-magnetron sputtering is used to grow Cr0.28Zr0.10O0.61 coatings at 500 degrees C. Coatings are annealed at 750 degrees C, 810 degrees C, and 870 degrees C. The microstructure evolution of the pseudobinary oxide compound is characterized through high resolution state of the art HRSTEM and HREDX-maps, revealing the segregation of Cr and Zr on the nm scale. The as-deposited coating comprises cc-(Cr,Zr)(2)O-3 solid solution with a Zr-rich (Zr,Cr)O-x. amorphous phase. After annealing to 750 degrees C tetragonal ZrO2 nucleates and grows from the amorphous phase. The ZrO2 phase is stabilized in its tetragonal structure at these fairly low annealing temperatures, possibly due to the small grain size (below 30 nm). Correlated with the nucleation and growth of the tetragonal-ZrO2 phase is an increase in hardness, with a maximum hardness after annealing to 750 degrees C, followed by a decrease in hardness upon coarsening, bcc metallic Cr phase formation and loss of oxygen, during annealing to 870 degrees C. The observed phase segregation opens up future design routes for pseudobinary oxides with tunable microstructural and mechanical properties. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.</p>","","","","","","","","","","","","","2017-06-19","2017-06-19","2018-03-27","","","12","","2","","","","","","false","","","" "1130127","Ektarawong, Annop [annek02] [0000-0002-6059-6833] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Max Planck Institute Eisenforsch GmbH, Germany)","First-principles prediction of stabilities and instabilities of compounds and alloys in the ternary B-As-P system","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","96","2","","","","2017","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.96.024202","000405697700005","","","urn:nbn:se:liu:diva-139554","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Research Council (VR) [621-2011-4417, 2014-4750]; International Career Grant [330-2014-6336]; Marie Sklodowska Curie Actions [INCA 600398]; CeNano at Linkoping University; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]</p>","<p>We examine the thermodynamic stability of compounds and alloys in the ternary B-As-P system theoretically using first-principles calculations. We demonstrate that the icosahedral B12As2 is the only stable compound in the binary B-As system, while the zinc-blende BAs is thermodynamically unstable with respect to B12As2 and the pure arsenic phase at 0 K, and increasingly so at higher temperature, suggesting that BAs may merely exist as a metastable phase. On the contrary, in the binary B-P system, both zinc-blende BP and icosahedral B12P2 are predicted to be stable. As for the binary As-P system, As1-xPx disordered alloys are predicted at elevated temperature-for example, a disordered solid solution of up to similar to 75 at.% As in black phosphorus as well as a small solubility of similar to 1 at.% P in gray arsenic at T = 750 K, together with the presence of miscibility gaps. The calculated large solubility of As in black phosphorus explains the experimental syntheses of black-phosphorus-type As1-xPx alloys with tunable compositions, recently reported in the literature. We investigate the phase stabilities in the ternary B-As-P system and demonstrate a high tendency for a formation of alloys in the icosahedral B-12(As1-xPx)(2) structure by intermixing of As and P atoms at the diatomic chain sites. The phase diagram displays noticeable mutual solubility of the icosahedral subpnictides in each other even at room temperature as well as a closure of a pseudobinary miscibility gap around 900 K. As for pseudobinary BAs1-xPx alloys, only a tiny amount of BAs is predicted to be able to dissolve in BP to form the BAs1-xPx disordered alloys at elevated temperature. For example, less than 5% of BAs can dissolve in BP at T = 1000 K. The small solubility limit of BAs in BP is attributed to the thermodynamic instability of BAs with respect to B12As2 and As.</p>","","","","","","","","","","","","","2017-08-08","2017-08-08","2018-08-29","","","3","","2","","","","","024202","false","","","" "908482","Wang, Weimin [weiwa49] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Yt- och Halvledarfysik [2233]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Olovsson, Weine [weiol14] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Uhrberg, Roger [roguh04] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Yt- och Halvledarfysik [2233]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Band structure of hydrogenated silicene on Ag(111): Evidence for half-silicane","Artikel i tidskrift","Refereegranskat","eng","PHYSICAL REVIEW B","2469-9950","published","93","8","","081406","","2016","","","","AMER PHYSICAL SOC","","","","","","10.1103/PhysRevB.93.081406","000369729000001","","","urn:nbn:se:liu:diva-125672","","","","Fysik (103)","","","<p>Funding Agencies|Swedish Research Council (VR) [621-2010-3746, 621-2014-4764, 621-2011-4426]; Linkoping Linnaeus Initiative for Novel Functional Materials - Swedish Research Council (VR) [2008-6582]; Swedish National Infrastructure for Computing (SNIC)</p>","<p>In the case of graphene, hydrogenation removes the conductivity due to the bands forming the Dirac cone by opening up a band gap. This type of chemical functionalization is of the utmost importance for electronic applications. As predicted by theoretical studies, a similar change in the band structure is expected for silicene, the closest analog to graphene. We here report a study of the atomic and electronic structures of hydrogenated silicene with hydrogen on one side, the so-called half-silicane. The (""2 root 3 x 2 root 3"") phase of silicene on Ag(111) was used in this Rapid Communication since it can be formed homogeneously across the entire surface of the Ag substrate. Low-energy electron diffraction and scanning tunneling microscopy data clearly show that hydrogenation changes the structure of silicene on Ag(111) resulting in a (1 x 1) periodicity with respect to the silicene lattice. The hydrogenated silicene also exhibits a quasiregular (""2 root 3 x 2 root 3"")-like arrangement of vacancies. Angle-resolved photoelectron spectroscopy revealed two dispersive bands which can be unambiguously assigned to half-silicane. The common top of these bands is located at similar to 0.9 eV below the Fermi level. We find that the experimental bands are closely reproduced by the theoretical band structure of free-standing silicene with H adsorbed on the upper hexagonal sublattice.</p>","","","","","","","","","","","","","2016-02-29","2016-03-02","2016-03-29","http://liu.diva-portal.org/smash/get/diva2:908482/FULLTEXT01.pdf","","3","","0","","","","","","false","","","" "947016","Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Max Planck Institute Eisenforsch GmbH, Germany);Koermann, F. (Max Planck Institute Eisenforsch GmbH, Germany; Delft University of Technology, Netherlands);Grabowski, B. (Max Planck Institute Eisenforsch GmbH, Germany);Glensk, A. (Max Planck Institute Eisenforsch GmbH, Germany);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (National University of Science and Technology MISIS, Russia);Neugebauer, J. (Max Planck Institute Eisenforsch GmbH, Germany)","Strong impact of lattice vibrations on electronic and magnetic properties of paramagnetic Fe revealed by disordered local moments molecular dynamics","Artikel i tidskrift","Refereegranskat","eng","PHYSICAL REVIEW B","2469-9950","published","93","22","","","","2016","","","","AMER PHYSICAL SOC","","","","","","10.1103/PhysRevB.93.224411","000377497800002","","","urn:nbn:se:liu:diva-130063","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Research Council (VR) [621-2011-4417, 330-2014-6336, 2015-04391]; Marie Sklodowska Curie Actions [INCA 600398]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFOMatLiU) [2009 00971]; Deutsche Forschungsgemeinschaft (DFG) [KO 5080/1-1]; European Research Council (ERC) under the European Union (EU) Seventh Framework Programme (FP7)/ERC [290998]; ERC under the EUs Horizon Research and Innovation Programme [639211]; Swedish Foundation for Strategic Research (SSF) program SRL Grant [10-0026]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005, RFMEFI58715X0023]</p>","<p>We study the impact of lattice vibrations on magnetic and electronic properties of paramagnetic bcc and fcc iron at finite temperature, employing the disordered local moments molecular dynamics (DLM-MD) method. Vibrations strongly affect the distribution of local magnetic moments at finite temperature, which in turn correlates with the local atomic volumes. Without the explicit consideration of atomic vibrations, the mean local magnetic moment and mean field derived magnetic entropy of paramagnetic bcc Fe are larger compared to paramagnetic fcc Fe, which would indicate that the magnetic contribution stabilizes the bcc phase at high temperatures. In the present study we show that this assumption is not valid when the coupling between vibrations and magnetism is taken into account. At the gamma-delta transition temperature (1662 K), the lattice distortions cause very similar magnetic moments of both bcc and fcc structures and hence magnetic entropy contributions. This finding can be traced back to the electronic densities of states, which also become increasingly similar between bcc and fcc Fe with increasing temperature. Given the sensitive interplay of the different physical excitation mechanisms, our results illustrate the need for an explicit consideration of vibrational disorder and its impact on electronic and magnetic properties to understand paramagnetic Fe. Furthermore, they suggest that at the gamma-delta transition temperature electronic and magnetic contributions to the Gibbs free energy are extremely similar in bcc and fcc Fe.</p>","","","","","","","","","","","","","2016-07-06","2016-07-06","2016-07-27","http://liu.diva-portal.org/smash/get/diva2:947016/FULLTEXT01.pdf","","6","","0","","","","","224411","false","","","" "921615","Sangiovanni, Davide [davsa82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Hellman, Olle [olohe96] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Max Planck Institute Eisenforsch GmbH, Germany);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (National University of Science and Technology MISIS, Russia; Tomsk State University, Russia)","Efficient and accurate determination of lattice-vacancy diffusion coefficients via non equilibrium ab initio molecular dynamics","Artikel i tidskrift","Refereegranskat","eng","PHYSICAL REVIEW B","2469-9950","published","93","9","","094305","","2016","","","","AMER PHYSICAL SOC","","","","","","10.1103/PhysRevB.93.094305","000372711200003","","","urn:nbn:se:liu:diva-127268","","","","Fysik (103)","","","<p>Funding Agencies|Knut and Alice Wallenberg Foundation [2011.0094]; Swedish Research Council (VR) [621-2011-4417, 2015-04391, 637-2013-7296, 330-2014-336]; Linkoping Linnaeus Initiative LiLi-NFM [2008-6572]; Swedish Government Strategic Research Area Grant in Materials Science on Advanced Functional Materials [MatLiU 2009-00971]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Tomsk State University Academic D. I. Mendeleev Fund Program</p>","<p>We revisit the color-diffusion algorithm [Aeberhard et al., Phys. Rev. Lett. 108, 095901 (2012)] in non equilibrium ab initio molecular dynamics (NE-AIMD) and propose a simple efficient approach for the estimation of monovacancy jump rates in crystalline solids at temperatures well below melting. Color-diffusion applied to monovacancy migration entails that one lattice atom (colored atom) is accelerated toward the neighboring defect site by an external constant force F. Considering bcc molybdenum between 1000 and 2800 K as a model system, NE-AIMD results show that the colored-atom jump rate k(NE) increases exponentially with the force intensity F, up to F values far beyond the linear-fitting regime employed previously. Using a simple model, we derive an analytical expression which reproduces the observed k(NE)(F) dependence on F. Equilibrium rates extrapolated by NE-AIMD results are in excellent agreement with those of unconstrained dynamics. The gain in computational efficiency achieved with our approach increases rapidly with decreasing temperatures and reaches a factor of 4 orders of magnitude at the lowest temperature considered in the present study.</p>","","","","","","","","","","","","","2016-04-19","2016-04-20","2016-05-10","http://liu.diva-portal.org/smash/get/diva2:921615/FULLTEXT01.pdf","","4","","0","","","","","","false","","","" "972648","Sernelius, Bo E. [bose02] [0000-0002-6281-868X] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Core-level spectra from bilayer graphene","Artikel i tidskrift","Refereegranskat","eng","FlatChem","2452-2627","published","1","","","6","10","2016","","","","Elsevier","","","","","","10.1016/j.flatc.2016.08.002","","","","urn:nbn:se:liu:diva-131467","","","graphene;core-level spectra;bilayer;collective modes","Fysik (103)","","","","<p>We derive core-level spectra for doped free-standing bilayer graphene. Numerical results are presented for all nine combinations of the doping concentrations 10¹² cm^-2; 10¹³ cm^-2, and 10¹⁴ cm^-2 in the two graphene sheets and we compare the results to the reference spectra for monolayer graphene. We furthermore discuss the spectrum of single-particle inter-band and intra-band excitations in the ωq-plane, and show how the dispersion curves of the collective modes are modified in the bilayer system.</p>","","","","","","","","","","","","","2016-09-21","2016-09-21","2016-09-29","","","1","","1","","","","","","true","","","" "1057481","Jason, Peter [petja31] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Johansson, Magnus [magjo23] [0000-0001-6708-1560] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Quantum signatures of charge flipping vortices in the Bose-Hubbard trimer","Artikel i tidskrift","Refereegranskat","eng","PHYSICAL REVIEW E","2470-0045","published","94","5","","","","2016","","","","AMER PHYSICAL SOC","","","","","","10.1103/PhysRevE.94.052215","000388277300006","27967094","","urn:nbn:se:liu:diva-133265","","","","Subatomär fysik (10301)","","","","<p>In this work we study quantum signatures of charge flipping vortices, found in the classical discrete nonlinear Schrodinger trimer, by use of the Bose-Hubbard model. We are able to identify such signatures in the quantum energy eigenstates, for instance when comparing the site amplitudes of the classical charge flipping vortices with the probability distribution over different particle configurations. It is also discussed how to construct quantum states that correspond to the classical charge flipping vortices and which effects can lead to deviations between the classical and quantum dynamics. We also examine properties of certain coherent states: classical-like quantum states that can be used to derive the classical model. Several quantum signatures are identified when studying the dynamics of these coherent states, for example, when comparing the average number of particles on a site with the classical site amplitude, when comparing the quantum and classical currents and topological charge, and when studying the evolution of the quantum probability amplitudes. The flipping of the quantum currents are found to be an especially robust feature of these states.</p>","","","","","","","","","","","","","2016-12-15","2016-12-18","2017-01-08","http://liu.diva-portal.org/smash/get/diva2:1057481/FULLTEXT01.pdf","","2","","0","","","","","052215","false","","","" "1071695","Morchutt, Claudius (Max Planck Institute Solid State Research, Germany; Ecole Polytech Federal Lausanne, Switzerland);Björk, Jonas [jonbj66] [0000-0002-1345-0006] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Strasser, Carola (Max Planck Institute Solid State Research, Germany);Starke, Ulrich (Max Planck Institute Solid State Research, Germany);Gutzler, Rico (Max Planck Institute Solid State Research, Germany);Kern, Klaus (Max Planck Institute Solid State Research, Germany; Ecole Polytech Federal Lausanne, Switzerland)","Interplay of Chemical and Electronic Structure on the Single-Molecule Level in 2D Polymerization","Artikel i tidskrift","Refereegranskat","eng","ACS NANO","1936-0851","","published","10","12","","11511","11518","2016","","","","AMER CHEMICAL SOC","","","","","","","10.1021/acsnano.6b07314","000391079700099","28024333","","urn:nbn:se:liu:diva-134307","","","covalent coupling; 2D polymer; electronic structure; STS; decarboxylation; porous polymer; HOMO/LUMO gap","Materialkemi (10403)","","","","<p>Single layers of covalently linked organic materials in the form of two-dimensional (2D) polymers constitute structures complementary to inorganic 2D materials. The electronic properties of 2D polymers may be manipulated through a deliberate choice of the organic precursors. Here we address the changes in electronic CO structure-from precursor molecule to oligomer by scanning tunneling spectroscopy and ultraviolet photoelectron spectroscopy. For this purpose, we introduce the polymerization reaction of 1,3,5-tris(4-carboxyphenyl)benzene via decarboxylation on Cu(111), which is thoroughly characterized by scanning tunneling microscopy, X-ray photoelectron spectroscopy, and density functional theory calculations. We present a comprehensive study of a contamination-free on-surface coupling scheme and study how dehydrogenation, decarboxylation, and polymerization affect the electronic structure on the molecular level.</p>","","","","","","","","","","","","","2017-02-03","2017-02-06","2017-02-06","","","6","","0","","","","","","false","","","" "1069826","Dewandre, Antoine (University of Liege, Belgium);Hellman, Olle [olohe96] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (CALTECH, CA 91125 USA);Bhattacharya, Sandip (Ruhr University of Bochum, Germany);Romero, Aldo H. (West Virginia University, WV 26506 USA; Benemerita University of Autonoma Puebla, Mexico);Madsen, Georg K. H. (TU Wien, Austria);Verstraete, Matthieu J. (University of Liege, Belgium)","Two-Step Phase Transition in SnSe and the Origins of its High Power Factor from First Principles","Artikel i tidskrift","Refereegranskat","eng","PHYSICAL REVIEW LETTERS","0031-9007","","published","117","27","","","","2016","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevLett.117.276601","000391034800002","28084752","","urn:nbn:se:liu:diva-134211","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|NSF [1434897]; American Chemical Society Petroleum Research Fund [54075-ND10]; ULg; Actions De Recherche Concertees (ACR) grants from Communaute Francaise de Belgique [10/15-03, 15/19-09]; COST network EUSpec [MP1306]; COST network XLIC [CM1204]; EU [RI-312763]; Knut &amp; Alice Wallenberg Foundation (KAW) project ""Isotopic Control for Ultimate Material Properties""; Swedish Foundation for Strategic Research (SSF) program [SRL10-002]</p>","<p>The interest in improving the thermoelectric response of bulk materials has received a boost after it has been recognized that layered materials, in particular SnSe, show a very large thermoelectric figure of merit. This result has received great attention while it is now possible to conceive other similar materials or experimental methods to improve this value. Before we can now think of engineering this material it is important we understand the basic mechanism that explains this unusual behavior, where very low thermal conductivity and a high thermopower result from a delicate balance between the crystal and electronic structure. In this Letter, we present a complete temperature evolution of the Seebeck coefficient as the material undergoes a soft crystal transformation and its consequences on other properties within SnSe by means of first-principles calculations. Our results are able to explain the full range of considered experimental temperatures.</p>","","","","","","","","","","","","","2017-01-29","2017-01-30","2017-02-17","http://liu.diva-portal.org/smash/get/diva2:1069826/FULLTEXT01.pdf","","6","","0","","","","","276601","false","","","" "936037","Nuala, M.Caffrey [nuaca84] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Johansson, Leif I [leijo19] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Xia, Chao [chaxi72] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Armiento, Rickard [ricar47] [0000-0002-5571-0814] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (NUST MISIS, Russia; Tomsk State University, Russia);Jacobi, Chariya [chavi32] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Structural and electronic properties of Li-intercalated graphene on SiC(0001)","Artikel i tidskrift","Refereegranskat","eng","Physical Review B: covering condensed matter and materials physics","2469-9950","","published","93","19","","195421-1","195421-9","2016","","","","American Physical Society","","","","","","","10.1103/PhysRevB.93.195421","000376248200006","","","urn:nbn:se:liu:diva-129161","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Research Council (VR) [621-2011-4252, 621-2011-4426]; Swedish Foundation for Strategic Research (SSF) program [10-0026]; European Union Seventh Framework Programme, Graphene Flagship [604391]; Swedish Government Strategic Research Areas SeRC and in Materials Science on Functional Materials at Link oping University [2009 00971]; SRC VR Grant [621-2011-4249]; Linnaeus Environment at Linkoping on Nanoscale Functional Materials (LiLi-NFM) - VR; Grant of Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Tomsk State University Academic D. I. Mendeleev Fund Program [8.1.18.2015]</p>","<p>We investigate the structural and electronic properties of Li-intercalated monolayer graphene on SiC(0001) using combined angle-resolved photoemission spectroscopy and first-principles density functional theory. Li intercalates at room temperature both at the interface between the buffer layer and SiC and between the two carbon layers. The graphene is strongly n-doped due to charge transfer from the Li atoms and two pi bands are visible at the (K) over bar point. After heating the sample to 300 degrees C, these pi bands become sharp and have a distinctly different dispersion to that of Bernal-stacked bilayer graphene. We suggest that the Li atoms intercalate between the two carbon layers with an ordered structure, similar to that of bulk LiC6. An AA stacking of these two layers becomes energetically favourable. The pi bands around the (K) over bar point closely resemble the calculated band structure of a C6LiC6 system, where the intercalated Li atoms impose a superpotential on the graphene electronic structure that opens gaps at the Dirac points of the two pi cones.</p>","","","","","","","","","","","","","2016-06-13","2016-06-13","2016-07-11","http://liu.diva-portal.org/smash/get/diva2:936037/FULLTEXT01.pdf","","6","","0","","","","","","true","","","" "1054707","Mosyagin, Igor [igomo87] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Hellman, Olle [olohe96] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Olovsson, Weine [weiol14] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (NUST MISIS, Russia)","Highly Efficient Free Energy Calculations of the Fe Equation of State Using Temperature-Dependent Effective Potential Method","Artikel i tidskrift","Refereegranskat","eng","Journal of Physical Chemistry A","1089-5639","1520-5215","published","120","43","","8761","8768","2016","","","","American Chemical Society (ACS)","","","","","","","10.1021/acs.jpca.6b08633","000387198600028","27700093","","urn:nbn:se:liu:diva-132993","","","","Teoretisk kemi (10407)","","","<p>Funding Agencies|Swedish Foundation for Strategic Research (SSF) program SRL [10-0026]; Swedish Research Council (VR) [2015-04391, 2014-4750, 637-2013-7296]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; PRACE-2IP project [FP7 RI-283493]</p>","<p>Free energy calculations at finite temperature based on ab initio molecular dynamics (AIMD) simulations have become possible, but they are still highly computationally demanding. Besides, achieving simultaneously high accuracy of the calculated results and efficiency of the computational algorithm is still a challenge. In this work we describe an efficient algorithm to determine accurate free energies of solids in simulations using the recently proposed temperature-dependent effective potential method (TDEP). We provide a detailed analysis of numerical approximations employed in the TDEP algorithm. We show that for a model system considered in this work, hcp Fe, the obtained thermal equation of state at 2000 K is in excellent agreement with the results of standard calculations within the quasiharmonic approximation.</p>","","","","","","","","","","","","","2016-12-07","2016-12-09","2017-04-24","","","5","","2","urn:nbn:se:liu:diva-136447","","","","","true","","","" "1109037","Finzel, Kati [katfi97] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Ayers, Paul W. (McMaster University, Canada)","Functional constructions with specified functional derivatives","Artikel i tidskrift","Refereegranskat","eng","Theoretical Chemistry accounts","1432-881X","1432-2234","published","135","12","","","","2016","","","","SPRINGER","","","","","","","10.1007/s00214-016-2013-7","000401837300001","","","urn:nbn:se:liu:diva-138322","","","Potential functionals; Specified functional derivatives; Orbital-free density functional theory; Pauli potential; Kinetic energy density functional","Teoretisk kemi (10407)","","","<p>Funding Agencies|Alexander von Humboldt foundation; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]; NSERC; Compute Canada</p>","<p>A bifunctional construction depending on a specified density-potential pair and an approximate guiding electron density functional is presented. The proposed bifunctional construction properly transforms under homogeneous coordinate scaling and yields the specified functional derivative, which determines the electron density. Whereas the method is general and applicable to all functional types, it will prove especially helpful in the context of orbital-free density functional theory, where most existing approximate density functionals predict inaccurate potentials.</p>","","","","","","","","","","","","","2017-06-13","2017-06-13","2017-06-13","","","2","","1","","","","","255","false","","","" "954718","Mozafari, Elham [elhmo04] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk kemi [16855]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Shulumba, Nina [ninsh46] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Steneteg, Peter [petst55] (Linköpings universitet [276], Institutionen för teknik och naturvetenskap [296], Medie- och Informationsteknik [6850]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, Germany);Abrikosov, Igor A. [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Materials Modeling and Development Laboratory, NUST “MISIS”, Moscow, Russia)","Finite-temperature elastic constants of paramagnetic materials within the disordered local moment picture from ab initio molecular dynamics calculations","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","94","5","","","","2016","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.94.054111","000381475300002","","","urn:nbn:se:liu:diva-130779","","","","Fysik (103);Den kondenserade materiens fysik (10304)","","","<p>Funding agencies. Swedish Research Council (VR) [621-2011-4426, 621-2011-4417, 330-2014-6336]; Swedish Foundation for Strategic Research (SSF) program SRL [10-0026]; Ministry of Education and Science of the Russian Federation [K2-2016-013, 14.Y26.31.0005]; Marie Sklodowska</p>","<p>We present a theoretical scheme to calculate the elastic constants of magnetic materials in the high-temperature paramagnetic state. Our approach is based on a combination of disordered local moments picture and ab initio molecular dynamics (DLM-MD). Moreover, we investigate a possibility to enhance the efficiency of the simulations of elastic properties using the recently introduced method: symmetry imposed force constant temperature-dependent effective potential (SIFC-TDEP). We have chosen cubic paramagnetic CrN as a model system. This is done due to its technological importance and its demonstrated strong coupling between magnetic and lattice degrees of freedom. We have studied the temperature-dependent single-crystal and polycrystalline elastic constants of paramagentic CrN up to 1200 K. The obtained results at T = 300 K agree well with the experimental values of polycrystalline elastic constants as well as the Poisson ratio at room temperature. We observe that the Young’s modulus is strongly dependent on temperature, decreasing by 14% from T = 300 K to 1200 K. In addition we have studied the elastic anisotropy of CrN as a function of temperature and we observe that CrN becomes substantially more isotropic as the temperature increases. We demonstrate that the use of Birch law may lead to substantial errors for calculations of temperature induced changes of elastic moduli. The proposed methodology can be used for accurate predictions of mechanical properties of magnetic materials at temperatures above their magnetic order-disorder phase transition.</p>","","","","","","","","","","","","","2016-08-23","2016-08-23","2016-09-26","http://liu.diva-portal.org/smash/get/diva2:954718/FULLTEXT01.pdf","","5","","0","urn:nbn:se:liu:diva-130517","","","","054111","true","","","" "972700","Faber, Felix A. (Department of Chemistry, University of Basel, Switzerland);Lindmaa, Alexander [aleli16] [0000-0001-5439-711X] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);von Lilienfeld, O. Anatole (Department of Chemistry, University of Basel, Switzerland);Armiento, Rickard [ricar47] [0000-0002-5571-0814] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Machine Learning Energies of 2 Million Elpasolite (AB₂D₆₎ Crystals","Artikel i tidskrift","Refereegranskat","eng","Physical Review Letters","0031-9007","1079-7114","published","117","13","","","","2016","","","","American Physical Society","","","","","","","10.1103/PhysRevLett.117.135502","000383849400010","","","urn:nbn:se:liu:diva-131473","","","Machine learning;AI;Elpasolite;Materials","Den kondenserade materiens fysik (10304)","","","<p>Funding agencies: Swiss National Science Foundation [PP00P2_138932]; Air Force Office of Scientific Research, Air Force Material Command, USAF [FA9550-15-1-0026]; NCCR MARVEL - Swiss National Science Foundation; Swiss National Supercomputing Centre (CSCS) [mr14]; Swedish R</p>","<p>Elpasolite is the predominant quaternary crystal structure (AlNaK2F6 prototype) reported in the Inorganic Crystal Structure Database. We develop a machine learning model to calculate density functional theory quality formation energies of all ∼2×10⁶ pristine <em>ABC₂D₆</em> elpasolite crystals that can be made up from main-group elements (up to bismuth). Our model’s accuracy can be improved systematically, reaching a mean absolute error of 0.1  eV/atom for a training set consisting of 10×10³ crystals. Important bonding trends are revealed: fluoride is best suited to fit the coordination of the <em>D</em> site, which lowers the formation energy whereas the opposite is found for carbon. The bonding contribution of the elements <em>A</em> and <em>B</em> is very small on average. Low formation energies result from <em>A</em> and <em>B</em> being late elements from group II, <em>C</em> being a late (group I) element, and <em>D</em> being fluoride. Out of 2×10⁶ crystals, 90 unique structures are predicted to be on the convex hull—among which is NFAl₂C_a6, with a peculiar stoichiometry and a negative atomic oxidation state for Al.</p>","","","","","","","","","","","","","2016-09-22","2016-09-22","2017-11-21","","Vetenskapsrådet [621-2011-4249,]","4","","2","urn:nbn:se:liu:diva-139767","","","","135502","true","","","" "951185","Sangiovanni, Davide [davsa82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Tasnadi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Hultman, Lars [larhu75] [0000-0002-2837-3656] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Petrov, Ivan [ivape26] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Illinois, USA);Greene, Joseph E [josgr17] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Illinois, USA);Chirita, Valeriu [valch35] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902])","N and Ti adatom dynamics on stoichiometric polar TiN(111) surfaces","Artikel i tidskrift","Refereegranskat","eng","Surface Science","0039-6028","1879-2758","published","649","","","72","79","2016","","","","ELSEVIER SCIENCE BV","","","","","","","10.1016/j.susc.2016.01.031","000379097000012","","","urn:nbn:se:liu:diva-130423","","","Surface diffusion; Nitrides; Molecular dynamics; Density functional theory; Polar surfaces","Teoretisk kemi (10407)","","","<p>Funding Agencies|Knut and Alice Wallenberg Foundation [2011.0094]; Swedish Research Council (VR) [2014-5790]; Linkoping Linnaeus Initiative LiLi-NFM [2008-6572]; Swedish Government Strategic Research Area Grant in Materials Science on Advanced Functional Materials through Swedens innovation agency VINNOVA [MatLiU 2009-00971]</p>","<p>We use molecular dynamics (MD) based on the modified embedded atom method (MEAM) to determine diffusion coefficients and migration pathways for Ti and N adatoms (Ti-ad and N-ad) on TiN(111). The reliability of the classical model-potential is verified by comparison with density functional theory (DFT) results at 0 K. MD simulations carried out at temperatures between 600 and 1800 K show that both Ti-ad and N-ad favor fcc surface sites and migrate among them by passing through metastable hcp positions. We find that N-ad species are considerably more mobile than Ti-ad on TiN(111); contrary to our previous results on TiN(001). In addition, we show that lattice vibrations at finite temperatures strongly modify the potential energy landscape and result in smaller adatom migration energies, E-a = 1.03 for Ti-ad and 0.61 eV for N-ad, compared to 0 K values E-aOK = 1.55 (Ti-ad) and 0.79 eV (N-ad). We also demonstrate that the inclusion of dipole corrections, neglected in previous DFT calculations, is necessary in order to obtain the correct formation energies for polar surfaces such as TiN(111). (C) 2016 Elsevier B.V. All rights reserved.</p>","","","","","","","","","","","","","2016-08-05","2016-08-07","2017-11-28","","","6","","1","","","","","","false","","","" "950633","Ohlin, Kjell (Ohlin Labs, Sweden);Berggren, Karl-Fredrik [karbe79] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Patterns beyond Faraday waves: observation of parametric crossover from Faraday instabilities to the formation of vortex lattices in open dual fluid strata","Artikel i tidskrift","Refereegranskat","eng","European journal of physics","0143-0807","1361-6404","published","37","4","","045803","","2016","","","","IOP PUBLISHING LTD","","","","","","","10.1088/0143-0807/37/4/045803","000378798800038","","","urn:nbn:se:liu:diva-130266","","","Faraday waves; parametric excitations; vortex lattices; streamline modelling; pattern formation; dual fluid strata; Topler/Rheinberg Schliren optics","Annan fysik (10399)","","","","<p>Faraday first characterised the behaviour of a fluid in a container subjected to vertical periodic oscillations. His study pertaining to hydrodynamic instability, the Faraday instability, has catalysed a myriad of experimental, theoretical, and numerical studies shedding light on the mechanisms responsible for the transition of a system at rest to a new state of well-ordered vibrational patterns at fixed frequencies. Here we study dual strata in a shallow vessel containing distilled water and high-viscosity lubrication oil on top of it. At elevated driving power, beyond the Faraday instability, the top stratum is found to freeze into a rigid pattern with maxima and minima. At the same time there is a dynamic crossover into a new state in the form of a lattice of recirculating vortices in the lower layer containing the water. Instrumentation and the physics behind are analysed in a phenomenological way together with a basic heuristic modelling of the wave field. The study, which is based on relatively low-budget equipment, stems from related art projects that have evolved over the years. The study is of value within basic research as well as in education, especially as more advanced collective project work in e.g. engineering physics, where it invites further studies of pattern formation, the emergence of vortex lattices and complexity.</p>","","","","","","","","","","","","","2016-07-28","2016-08-01","2017-11-28","http://liu.diva-portal.org/smash/get/diva2:950633/FULLTEXT01.pdf","","2","","1","","","","","","false","","","" "950594","Sangiovanni, Davide [davsa82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Mei, A. B. (University of Illinois, IL 61801 USA);Hultman, Lars [larhu75] [0000-0002-2837-3656] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Chirita, Valeriu [valch35] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Petrov, Ivan [ivape26] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Illinois, IL 61801 USA);Greene, Joseph E [josgr17] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Illinois, IL 61801 USA; University of Illinois, IL 61801 USA)","Ab Initio Molecular Dynamics Simulations of Nitrogen/VN(001) Surface Reactions: Vacancy-Catalyzed N-2 Dissociative Chemisorption, N Adatom Migration, and N-2 Desorption","Artikel i tidskrift","Refereegranskat","eng","The Journal of Physical Chemistry C","1932-7447","1932-7455","published","120","23","","12503","12516","2016","","","","AMER CHEMICAL SOC","","","","","","","10.1021/acs.jpcc.6b02652","000378196200021","","","urn:nbn:se:liu:diva-130283","","","","Oorganisk kemi (10404)","","","<p>Funding Agencies|Knut and Alice Wallenberg Foundation (Isotope Project) [2011.0094]; Swedish Research Council (VR) Linkoping Linnaeus Initiative LiLi-NFM [2008-6572, 2014-5790, 2013-4018]; Swedish Government Strategic Research Area Grant in Materials Science on Advanced Functional Materials (through Swedens innovation agency VINNOVA) [MatLiU 2009-00971]</p>","<p>We use density-functional ab initio molecular dynamics to investigate the kinetics of N/VN(001) surface reactions at temperatures ranging from 1600 to 2300 K. N adatoms (N-ad) on VN(001) favor epitaxial atop-V positions and diffuse among them by transiting through 4-fold hollow (FFH) sites, at which they are surrounded by two V and two N surface atoms. After several atop-V -amp;gt; FFH -amp;gt; atop-V jumps, isolated N adatoms bond strongly with an underlying N surface (N-surf) atom. Frequent N-ad/N-surf pair exchange reactions lead to N-2 desorption, which results in the formation of an anion surface vacancy. N vacancies rapidly migrate via in-plane (110) jumps and act as efficient catalysts for the dissociative chemisorption of incident N-2 molecules. During exposure of VN(001) to incident atomic N gas atoms, N-ad/N-ad recombination and desorption is never observed, despite a continuously high N monomer surface coverage. Instead, N-2 desorption is always initiated by a N adatom removing a N surface atom or by energetic N gas atoms colliding with N-ad or N-surf atoms. Similarities and differences between: N/VN(001) vs. previous N/TiN(001) results, discussed on the basis of temperature-dependent ab initio electronic structures and chemical bonding, provide insights for controlling the reactivity of NaCl-structure transition-metal nitride (001) surfaces via electron-concentration tuning.</p>","","","","","","","","","","","","","2016-07-28","2016-08-01","2017-11-28","http://liu.diva-portal.org/smash/get/diva2:950594/FULLTEXT01.pdf","","6","","1","","","","","","false","","","" "940490","Tal, Alexey [aleta94] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (National University of Science and Technology MISIS, Russia);Katsnelson, Mikhail I. (Radboud University of Nijmegen, Netherlands; Ural Federal University, Russia);Ekholm, Marcus [marek10] [0000-0002-7563-1494] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Jönsson, Johan [johjo06] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Dubrovinsky, Leonid (University of Bayreuth, Germany);Dubrovinskaia, Natalia (University of Bayreuth, Germany);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (National University of Science and Technology MISIS, Russia)","Pressure-induced crossing of the core levels in 5d metals","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","93","20","","205150","","2016","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.93.205150","000376638700004","","","urn:nbn:se:liu:diva-129490","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Government Strategic Research Area Grant Swedish e-Science Research Centre (SeRC); Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of MISiS; Swedish Foundation for Strategic Research (SSF) program SRL [10-0026]; Swedish Research Council (VR) [2015-04391]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; German Research Foundation (DFG); Federal Ministry of Education and Research (BMBF), Germany; DFG [DU 954-8/1]; BMBF (PT-DESY) [5K13WC3, O5K2013, 2]; Act 211 Government of the Russian Federation [02.A03.21.0006]; Knut and Alice Wallenberg Foundation [2012.0083, 2014-2019]</p>","<p>A pressure-induced interaction between core electrons, the core-level crossing (CLC) transition, has been observed in hcp Os at P approximate to 400 GPa [L. Dubrovinsky et al., Nature (London) 525, 226 (2015)]. By carrying out a systematic theoretical study for all metals of the 5d series (Hf, Ta, W, Re, Os, Ir, Pt, Au) we have found that the CLC transition is a general effect for this series of metals. While in Pt it occurs at approximate to 1500 GPa, at a pressure substantially higher than in Os, in Ir it occurs already at 80 GPa. Moreover, we predict that in Re the CLC transition may take place already at ambient pressure. We explain the effect of the CLC and analyze the shift of the transition pressure across the series within the Thomas-Fermi model. In particular, we show that the effect has many common features with the atomic collapse in rare-earth elements.</p>","","","","","","","","","","","","","2016-06-20","2016-06-21","2017-11-28","http://liu.diva-portal.org/smash/get/diva2:940490/FULLTEXT01.pdf","","7","","0","","","","","","false","","","" "954264","Finzel, Kati [katfi97] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Approximating the Pauli Potential in Bound Coulomb Systems","Artikel i tidskrift","Refereegranskat","eng","International Journal of Quantum Chemistry","0020-7608","1097-461X","published","116","16","","1261","1266","2016","","","","WILEY-BLACKWELL","","","","","","","10.1002/qua.25169","000379892800007","","","urn:nbn:se:liu:diva-130647","","","atomic shell structure; Pauli potential","Teoretisk kemi (10407)","","","<p>Funding Agencies|Alexander von Humboldt foundation; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]</p>","<p>It is shown that the Pauli potential in bound Coulomb systems can in good approximation be composed from the corresponding atomic fragments. This provides a simple and fast procedure how to generate the Pauli potential in bound systems, which is needed to perform an orbital-free density functional calculation. The method is applicable to molecules and solids. (c) 2016 Wiley Periodicals, Inc.</p>","","","","","","","","","","","","","2016-08-19","2016-08-22","2017-11-28","","","1","","1","","","","","","false","","","" "954265","Finzel, Kati [katfi97] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","About the Difference Between Density Functionals Defined by Energy Criterion and Density Functionals Defined by Density Criterion: Exchange Functionals","Artikel i tidskrift","Refereegranskat","eng","International Journal of Quantum Chemistry","0020-7608","1097-461X","published","116","15","","1187","1189","2016","","","","WILEY-BLACKWELL","","","","","","","10.1002/qua.25155","000379892500007","","","urn:nbn:se:liu:diva-130648","","","potential functional theory; exact exchange","Teoretisk kemi (10407)","","","<p>Funding Agencies|Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]</p>","<p>The difference between density functionals defined by energy criterion and density functionals defined by density criterion is studied for the exchange functional. It is shown that Slater potentials are exact exchange potentials in the sense that they yield the Hartree-Fock electron density if all operators are given by local expressions. (C) 2016 Wiley Periodicals, Inc.</p>","","","","","","","","","","","","","2016-08-19","2016-08-22","2017-11-28","","","1","","1","","","","","","false","","","" "952674","Edström, Daniel [daned22] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Sangiovanni, Davide [davsa82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Hultman, Lars [larhu75] [0000-0002-2837-3656] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Petrov, Ivan [ivape26] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Illinois, IL 61801 USA; University of Illinois, IL 61801 USA);Greene, Joseph E [josgr17] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Illinois, USA);Chirita, Valeriu [valch35] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Large-scale molecular dynamics simulations of TiN/TiN(001) epitaxial film growth","Artikel i tidskrift","Refereegranskat","eng","Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films","0734-2101","1520-8559","published","34","4","","041509-1","041509-9","2016","","","","AMER INST PHYSICS","","","","","","","10.1116/1.4953404","000379588000027","","","urn:nbn:se:liu:diva-130405","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Research Council (VR) Linkoping Linnaeus Initiative LiLi-NFM [2008-6572, 2009-00971, 2013-4018, 2014-5790]; Swedish Government Strategic Research Area Grant in Materials Science on Advanced Functional Materials; Knut and Alice Wallenberg Foundation (Isotope Project)</p>","<p>Large-scale classical molecular dynamics simulations of epitaxial TiN/TiN(001) thin film growth at 1200K are carried out using incident flux ratios N/Ti -1, 2, and 4. The films are analyzed as a function of composition, island size distribution, island edge orientation, and vacancy formation. Results show that N/Ti-1 films are globally understoichiometric with dispersed Ti-rich surface regions which serve as traps to nucleate 111-oriented islands, leading to local epitaxial breakdown. Films grown with N/Ti=2 are approximately stoichiometric and the growth mode is closer to layer-by-layer, while N/Ti-4 films are stoichiometric with N-rich surfaces. As N/Ti is increased from 1 to 4, island edges are increasingly polar, i. e., 110-oriented, and N-terminated to accommodate the excess N flux, some of which is lost by reflection of incident N atoms. N vacancies are produced in the surface layer during film deposition with N/Ti-1 due to the formation and subsequent desorption of N-2 molecules composed of a N adatom and a N surface atom, as well as itinerant Ti adatoms pulling up N surface atoms. The N vacancy concentration is significantly reduced as N/Ti is increased to 2; with N/Ti-4, Ti vacancies dominate. Overall, our results show that an insufficient N/Ti ratio leads to surface roughening via nucleation of small dispersed 111 islands, whereas high N/Ti ratios result in surface roughening due to more rapid upper-layer nucleation and mound formation. The growth mode of N/Ti-2 films, which have smoother surfaces, is closer to layer-by-layer. (C) 2016 American Vacuum Society.</p>","","","","","","","","","","","","","2016-08-05","2016-08-15","2017-11-28","http://liu.diva-portal.org/smash/get/diva2:952674/FULLTEXT01.pdf","","6","","1","urn:nbn:se:liu:diva-132272","","","","","false","","","" "936027","Finzel, Kati [katfi97] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","About the atomic shell structure in real space and the Pauli exclusion principle","Artikel i tidskrift","Refereegranskat","eng","Theoretical Chemistry accounts","1432-881X","1432-2234","published","135","6","","148","","2016","","","","SPRINGER","","","","","","","10.1007/s00214-016-1907-8","000376251100002","","","urn:nbn:se:liu:diva-129164","","","Atomic shell structure; Pauli exclusion principle; Atoms; Real-space properties","Teoretisk kemi (10407)","","","<p>Funding Agencies|Alexander von Humboldt foundation; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO Mat LiU) [2009 00971]</p>","<p>It is shown that any set of eigenfunctions (1s, 2s) of a bare Coulomb Hamiltonian exhibit the same atomic shell structure pattern for the real-space indicator a(1), which is defined as the ratio between the positive kinetic energy density and the electron density. Since this model Hamiltonian excludes all effects due to the electron-electron repulsion, the appearance of the atomic shell structure is attributed to the Pauli exclusion principle that arises from the requirements for a fermionic wavefunction. Since the derivation is independent of the nuclear charge and the energy of the system, reversely imposing proper atomic shell structure behavior in the design of kinetic energy functionals mimics the Pauli exclusion principle during a variational process.</p>","","","","","","","","","","","","","2016-06-13","2016-06-13","2017-11-28","","","1","","1","","","","","","false","","","" "1063078","Lindmaa, Alexander [aleli16] [0000-0001-5439-711X] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Armiento, Rickard [ricar47] [0000-0002-5571-0814] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Energetics of the AK13 semilocal Kohn-Sham exchange energy functional","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","94","15","","","","2016","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.94.155143","000390031400002","","","urn:nbn:se:liu:diva-133756","","","","Teoretisk kemi (10407)","","","<p>Funding Agencies|Swedish Research Council (VR) [621-2011-4249]; Linnaeus Environment at Linkoping on Nanoscale Functional Materials (LiLi-NFM) - VR; Swedish e-Science Research Centre (SeRC)</p>","<p>The recent nonempirical semilocal exchange functional of Armiento and Kummel [Phys. Rev. Lett. 111, 036402 (2013)], AK13, incorporates a number of features reproduced by higher-order theory. The AK13 potential behaves analogously with the discontinuous jump associated with the derivative discontinuity at integer particle numbers. Recent works have established that AK13 gives a qualitatively improved orbital description compared to other semilocal methods, and reproduces a band structure closer to higher-order theory. However, its energies and energetics are inaccurate. The present work further investigates the deficiency in energetics. In addition to AK13 results, we find that applying the local-density approximation (LDA) non-self-consistently on the converged AK13 density gives very reasonable energetics with equilibrium lattice constants and bulk moduli well described across 13 systems. We also confirm that the attractive orbital features of AK13 are retained even after full structural relaxation. Hence, the deficient energetics cannot be a result of the AK13 orbitals having adversely affected the quality of the electron density compared to that of usual semilocal functionals; an improved orbital description and good energetics are not in opposition. This is also confirmed by direct calculation of the principal component of the electric field gradient. In addition, we prove that the non-self-consistent scheme is equivalent to using a single external-potential-dependent functional in an otherwise consistent, nonvariational Kohn-Sham density-functional theory (KS DFT) scheme. Furthermore, our results also demonstrate that, while an internally consistent KS functional is presently missing, non-self-consistent LDA on AK13 orbitals works as a practical nonempirical computational scheme to predict geometries, bulk moduli, while retaining the band structure features of AK13 at the computational cost of semi-local DFT.</p>","","","","","","","","","","","","","2017-01-09","2017-01-09","2017-11-29","http://liu.diva-portal.org/smash/get/diva2:1063078/FULLTEXT01.pdf","","2","","0","urn:nbn:se:liu:diva-139767","","","","155143","false","","","" "1065049","Karimov, A. R. (Russian Academic Science, Russia; National Research Nucl University of MEPhI, Russia);Yu, M. Y. (Zhejiang University, Peoples R China; Ruhr University of Bochum, Germany);Stenflo, Lennart [lenst65] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Properties and evolution of anisotropic structures in collisionless plasmas","Artikel i tidskrift","Refereegranskat","eng","Journal of Plasma Physics","0022-3778","1469-7807","published","82","","","","","2016","","","","CAMBRIDGE UNIV PRESS","","","","","","","10.1017/S0022377816000805","000390383400012","","","urn:nbn:se:liu:diva-133896","","","plasma expansion; plasma flows; plasma nonlinear phenomena","Fusion, plasma och rymdfysik (10303)","","","<p>Funding Agencies|National Natural Science Foundation of China [11374262, 11475147]; State Key Laboratory of High Field Laser Physics at SIOM</p>","<p>A new class of exact electrostatic solutions of the Vlasov-Maxwell equations based on the Jeanss theorem is proposed for studying the evolution and properties of two-dimensional anisotropic plasmas that are far from thermodynamic equilibrium. In particular, the free expansion of a slab of electron-ion plasma into vacuum is investigated.</p>","","","","","","","","","","","","","2017-01-13","2017-01-13","2017-11-29","","","3","","1","","","","","905820502","false","","","" "1060075","Ivády, Viktor [vikiv58] (Linköpings universitet [276], Tekniska fakulteten [872902]) (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Hungarian Academic Science, Hungary);Klimov, Paul V. (University of Chicago, IL 60637 USA);Miao, Kevin C. (University of Chicago, IL 60637 USA);Falk, Abram L. (University of Chicago, IL 60637 USA; IBM TJ Watson Research Centre, NY 10598 USA);Christle, David J. (University of Chicago, IL 60637 USA);Szasz, Krisztian (Hungarian Academic Science, Hungary);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (National University of Science and Technology MISIS, Russia);Awschalom, David D. (University of Chicago, IL 60637 USA);Gali, Adam (Hungarian Academic Science, Hungary; Budapest University of Technology and Econ, Hungary)","High-Fidelity Bidirectional Nuclear Qubit Initialization in SiC","Artikel i tidskrift","Refereegranskat","eng","Physical Review Letters","0031-9007","1079-7114","published","117","22","","","","2016","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevLett.117.220503","000388630000005","27925750","","urn:nbn:se:liu:diva-133387","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Knut &amp; Alice Wallenberg Foundation; Swedish Research Council (VR) [2015-04391]; Swedish Foundation for Strategic Research program SRL Grant [10-0026]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Swedish National Infrastructure for Computing [SNIC 2013/1-331, SNIC 2014/1-420]; ""Lendulet program"" of the Hungarian Academy of Sciences; NSF [EFMA-1641099]; UChicago NSF-MRSEC; AFOSR, AFOSR-MURI, ARO</p>","<p>Dynamic nuclear polarization (DNP) is an attractive method for initializing nuclear spins that are strongly coupled to optically active electron spins because it functions at room temperature and does not require strong magnetic fields. In this Letter, we theoretically demonstrate that DNP, with near-unity polarization efficiency, can be generally realized in weakly coupled electron spin-nuclear spin systems. Furthermore, we theoretically and experimentally show that the nuclear spin polarization can be reversed by magnetic field variations as small as 0.8 Gauss. This mechanism offers new avenues for DNP-based sensors and radio-frequency free control of nuclear qubits.</p>","","","","","","","","","","","","","2016-12-22","2016-12-27","2017-11-29","http://liu.diva-portal.org/smash/get/diva2:1060075/FULLTEXT01.pdf","","9","","2","","","","","220503","false","","","" "1054734","Shulumba, Nina [ninsh46] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Saarland, Germany);Hellman, Olle [olohe96] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (CALTECH, CA 91125 USA);Raza, Zamaan [zamra51] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Max Planck Institute Eisenforsch GmbH, Germany);Barrirero, Jenifer [jenba07] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Saarland, Germany);Muecklich, Frank (University of Saarland, Germany);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (NUST MISIS, Russia);Odén, Magnus [magod41] [0000-0002-2286-5588] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Lattice Vibrations Change the Solid Solubility of an Alloy at High Temperatures","Artikel i tidskrift","Refereegranskat","eng","Physical Review Letters","0031-9007","1079-7114","published","117","20","","","","2016","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevLett.117.205502","000387401600009","27886477","","urn:nbn:se:liu:diva-132990","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Foundation for Strategic Research Programs (Stiftelsen for Strategisk Forskning) [SRL10-0026, RMA08-0069]; FUNCASE; Swedish Research Council (Vetenskapsradet) [2012-4401, 621-2011-4426, 2015-04391, 637-2013-7296, 621-2011-4417, 330-2014-6336]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]; Swedish Governmental Agency for Innovation Systems (Vinnova) through the M-ERA.net project MC2; SECO Tools AB; Marie Sklodowska Curie Actions, Cofund [INCA 600398]; Erasmus Mundus Joint European Doctoral Programme DocMASE; Ministry of Education and Science of the Russian Federation [K2-2016-013]; Deutsche Forschungsgemeinschaft; Federal State Government of Saarland [INST 256/298-1 FUGG]</p>","<p>We develop a method to accurately and efficiently determine the vibrational free energy as a function of temperature and volume for substitutional alloys from first principles. Taking Ti1-xAlxN alloy as a model system, we calculate the isostructural phase diagram by finding the global minimum of the free energy corresponding to the true equilibrium state of the system. We demonstrate that the vibrational contribution including anharmonicity and temperature dependence of the mixing enthalpy have a decisive impact on the calculated phase diagram of a Ti1-xAlxN alloy, lowering the maximum temperature for the miscibility gap from 6560 to 2860 K. Our local chemical composition measurements on thermally aged Ti0.5Al0.5N alloys agree with the calculated phase diagram.</p>","","","","","","","","","","","","","2016-12-07","2016-12-09","2017-11-29","http://liu.diva-portal.org/smash/get/diva2:1054734/FULLTEXT01.pdf","","8","","2","","","","","205502","false","","","" "1052430","Karimov, A. R. (Russian Academic Science, Russia; National Research Nucl University of MEPhI, Russia);Yu, M. Y. (Zhejiang University, Peoples R China; Ruhr University of Bochum, Germany);Stenflo, Lennart [lenst65] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","A new class of exact solutions for Vlasov-Poisson plasmas","Artikel i tidskrift","Refereegranskat","eng","Physica Scripta","0031-8949","1402-4896","published","91","11","","114002","","2016","","","","IOP PUBLISHING LTD","","","","","","","10.1088/0031-8949/91/11/114002","000386613000001","","","urn:nbn:se:liu:diva-132844","","","nonlinear evolution; plasma expansion; surface oscillations; Vlasov-Poisson plasma","Fusion, plasma och rymdfysik (10303)","","","<p>Funding Agencies|National Natural Science Foundation of China [11374262, 11475147]; State Key Laboratory of High Field Laser Physics at SIOM</p>","<p>A new class of exact solutions of the Vlasov-Poisson equations based on the Jeans theorem is considered. The self-consistent solutions for the evolution of the system from given initial particle distributions make use of particular invariants of particle motion with predetermined spatial structure. The relation between the time-dependent coefficients of the latter and the macroscopic plasma quantities, or moments of the distribution function, are obtained. As an illustration, the evolution of an expanding plasma with oscillations of the electron and ion expansion fronts is presented.</p>","","","","","","","","","","","","","2016-11-30","2016-12-06","2017-11-29","","","3","","1","","","","","","false","","","" "1052464","Klarbring, Johan [johkl85] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Vekilova, Olga Yu. (KTH Royal Institute Technology, Sweden; Uppsala University, Sweden);Nilsson, Johan O. (KTH Royal Institute Technology, Sweden);Skorodumova, Natalia V. (KTH Royal Institute Technology, Sweden; Uppsala University, Sweden);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Ionic conductivity in Sm-doped ceria from first-principles non-equilibrium molecular dynamics","Artikel i tidskrift","Refereegranskat","eng","Solid State Ionics","0167-2738","1872-7689","published","296","","","47","53","2016","","","","ELSEVIER SCIENCE BV","","","","","","","10.1016/j.ssi.2016.08.011","000386743400009","","","urn:nbn:se:liu:diva-132831","","","","Materialkemi (10403)","","","<p>Funding Agencies|Swedish Energy Agency (STEM) [35515-1]; Carl Tryggers Foundation [CTS 14:433]; Swedish Research Council (VR) [2014-5993, 2014-4750]; LiLi-NFM; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]</p>","<p>Sm-doped ceria is a prospective electrolyte material for intermediate-temperature solid-oxide fuel cells (IT-SOFC). Equilibrium ab initio molecular dynamics (AIMD) studies of oxygen ion diffusion in this material are currently impractical due to the rareness of diffusive events on the accessible timescale. To overcome this issue we have performed ab initio non-equilibrium molecular dynamics calculations of Sm-doped ceria using the color diffusion algorithm. Applying an external force field we have been able to increase the frequency of diffusive events over the simulation time, while keeping the physical mechanism of diffusion intact. We have investigated the temperature dependence of the maximum strength of the applied external field that could be used while maintaining the response of the system in a linear regime. This allows one to obtain the diffusivity at zero field. The bulk ionic conductivity has been calculated and found to match the experimental data well. We have also compared the description of the diffusion process by our method to previous findings and show that the migration mechanism and site preference of oxygen vacancies with respect to the Sm dopants is well reproduced. (C) 2016 Elsevier B.V. All rights reserved.</p>","","","","","","","","","","","","","2016-11-30","2016-12-06","2017-11-29","","","5","","1","","","","","","false","","","" "1048328","Leonov, I. (University of Augsburg, Germany; National University of Science and Technology MISIS, Russia);Pourovskii, L. (National University of Science and Technology MISIS, Russia; University of Paris Saclay, France; Coll France, France);Georges, A. (University of Paris Saclay, France; Coll France, France; University of Geneva, Switzerland);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (National University of Science and Technology MISIS, Russia)","Magnetic collapse and the behavior of transition metal oxides at high pressure","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","94","15","","155135","","2016","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.94.155135","000386099300003","","","urn:nbn:se:liu:diva-132666","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Deutsche Forschungsgemeinschaft through Transregio [TRR 80]; Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of NUST ""MISIS"" [K3-2016-027]; European Research Council [ERC-319286 QMAC]; Swiss National Science Foundation (NCCR MARVEL); Swedish Research Council (VR) [2015-04391]; Swedish Foundation for Strategic Research (SSF) [SRL 10-0026]; Knut and Alice Wallenberg Foundation [2014-2019]; Swedish Government Strategic Research Area Grant Swedish e-Science Research Centre (SeRC); Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]</p>","<p>We report a detail theoretical study of the electronic structure and phase stability of transition metal oxides MnO, FeO, CoO, and NiO in their paramagnetic cubic B1 structure by employing dynamical mean-field theory of correlated electrons combined with ab initio band-structure methods. Our calculations reveal that under pressure these materials exhibit a Mott insulator-metal transition (IMT) which is accompanied by a simultaneous collapse of local magnetic moments and lattice volume, implying a complex interplay between chemical bonding and electronic correlations. Moreover, our results for the transition pressure show a monotonous decrease from similar to 145 to 40 GPa, upon moving from MnO to CoO. In contrast to that, in NiO, magnetic collapse is found to occur at a remarkably higher pressure of similar to 429 GPa. We provide a unified picture of such a behavior and suggest that it is primarily a localized to itinerant moment behavior transition at the IMT that gives rise to magnetic collapse in transition metal oxides.</p>","","","","","","","","","","","","","2016-11-18","2016-11-21","2017-11-29","http://liu.diva-portal.org/smash/get/diva2:1048328/FULLTEXT01.pdf","","4","","0","","","","","","false","","","" "1048335","Bosak, A. (European Synchrotron Radiat Facil, France);Krisch, M. (European Synchrotron Radiat Facil, France);Chumakov, A. (European Synchrotron Radiat Facil, France);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (National University of Science and Technology MISIS, Russia);Dubrovinsky, L. (University of Bayreuth, Germany)","Possible artifacts in inferring seismic properties from X-ray data","Artikel i tidskrift","Refereegranskat","eng","Physics of the Earth and Planetary Interiors","0031-9201","1872-7395","published","260","","","14","19","2016","","","","ELSEVIER SCIENCE BV","","","","","","","10.1016/j.pepi.2016.08.007","000386188200002","","","urn:nbn:se:liu:diva-132660","","","Elastic averaging; Seismology; X-rays; Iron","Geofysik (10505)","","","<p>Funding Agencies|Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of NUST ""MISIS"" [K2-2016-013, 14.Y26.31.0005]; Swedish Research Council (VR) [2015-04391]</p>","<p>We consider the experimental and computational artifacts relevant for the extraction of aggregate elastic properties of polycrystalline materials with particular emphasis on the derivation of seismic velocities. We use the case of iron as an example, and show that the improper use of definitions and neglecting the crystalline anisotropy can result in unexpectedly large errors up to a few percent. (C) 2016 Elsevier B.V. All rights reserved.</p>","","","","","","","","","","","","","2016-11-18","2016-11-21","2017-11-29","","","5","","1","","","","","","false","","","" "1048139","Wang, You-Mei (Hangzhou Dianzi University, Peoples R China);Yu, M. Y. (Zhejiang University, Peoples R China; Ruhr University, Germany);Stenflo, Lennart [lenst65] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Karimov, A. R. (Russian Academic Science, Russia; National Research Nucl University of MEPhI, Russia)","Evolution of a Cold Non-neutral Electron-Positron Plasma Slab","Artikel i tidskrift","Refereegranskat","eng","Chinese Physics Letters","0256-307X","1741-3540","published","33","8","","085205","","2016","","","","IOP PUBLISHING LTD","","","","","","","10.1088/0256-307X/33/8/085205","000386179400019","","","urn:nbn:se:liu:diva-132688","","","","Fusion, plasma och rymdfysik (10303)","","","<p>Funding Agencies|National Natural Science Foundation of China [11247007, 11374262, 11475147]; Natural Science Foundation of Zhejiang Province [LY15A050001]; Fundamental Research Funds for Central Universities; Open Fund of the State Key Laboratory of High Field Laser Physics at SIOM</p>","<p>Evolution of a non-neutral cold electron-positron plasma slab is investigated. Initially the slab consists of a quasineutral plasma core bounded on both sides by layers containing only positrons (or electrons). Results from a nonperturbative, or mathematically exact, analysis of the governing fluid conservation equations and the Poisson equation show that despite their equal mass and charge magnitude, the electron and positron fronts can expand separately as well as a single fluid, and that nonlinear surface oscillations can be excited on the expansion fronts.</p>","","","","","","","","","","","","","2016-11-18","2016-11-20","2017-11-29","","","4","","1","","","","","","false","","","" "1033245","Nowakowska, Sylwia (Department of Physics, University of Basel, Basel, Switzerland);Wäckerlin, Aneliia (Department of Physics, University of Basel, Basel, Switzerland);Piquero-Zulaica, Ignacio (Centro de Física de Materiales (CSIC/UPV-EHU)—Materials Physics Center, San Sebastián, Spain);Nowakowski, Jan (Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, Villigen, PSI, Switzerland);Kawai, Shigeki (Department of Physics, University of Basel, Basel, Switzerland; PRESTO, Japan Science and Technology Agency (JST), Kawaguchi, Saitama, Japan);Wäckerlin, Christian (Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, Villigen, PSI, Switzerland);Matena, Manfred (Department of Physics, University of Basel, Basel, Switzerland; Donostia International Physics Center (DIPC), San Sebastián, Spain);Nijs, Thomas (Department of Physics, University of Basel, Basel, Switzerland);Fatayer, Shadi (Department of Physics, University of Basel, Basel, Switzerland; Departamento de Física Aplicada, Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, Campinas, Brazil);Popova, Olha (Department of Physics, University of Basel, Basel, Switzerland);Ahsan, Aisha (Department of Physics, University of Basel, Basel, Switzerland);Mousavi, S. Fatemeh (Department of Physics, University of Basel, Basel, Switzerland);Ivas, Toni (Department of Physics, University of Basel, Basel, Switzerland);Meyer, Ernst (Department of Physics, University of Basel, Basel, Switzerland);Stöhr, Meike (Zernike Institute for Advanced Materials, University of Groningen, AG, Groningen, The Netherlands);Ortega, J. Enrique (Centro de Física de Materiales (CSIC/UPV-EHU)—Materials Physics Center, San Sebastián, Spain; Donostia International Physics Center (DIPC), San Sebastián, Spain; Departamento Física Aplicada I, Universidad del País Vasco, San Sebastián, Spain);Björk, Jonas [jonbj66] [0000-0002-1345-0006] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk kemi [16855]) (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Gade, Lutz H. (Anorganisch-Chemisches Institut, Universität Heidelberg, Heidelberg, Germany);Lobo-Checa, Jorge (Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC-Universidad de Zaragoza, Zaragoza, Spain; Departamento de Física de la Materia Condensada, Universidad de Zaragoza, Zaragoza, Spain);Jung, Thomas A. (Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, Villigen, PSI, Switzerland)","Configuring Electronic States in an Atomically Precise Array of Quantum Boxes","Artikel i tidskrift","Refereegranskat","eng","Small","1613-6810","1613-6829","published","12","28","","3757","3763","2016","","","","Wiley-VCH Verlagsgesellschaft","","","","","","","10.1002/smll.201600915","000383375100002","27276517","","urn:nbn:se:liu:diva-131787","","","","Fysikalisk kemi (10402);Den kondenserade materiens fysik (10304);Teoretisk kemi (10407)","","","","<p>A 2D array of electronically coupled quantum boxes is fabricated by means of on-surface self-assembly assuring ultimate precision of each box. The quantum states embedded in the boxes are configured by adsorbates, whose occupancy is controlled with atomic precision. The electronic interbox coupling can be maintained or significantly reduced by proper arrangement of empty and filled boxes.</p>","","","","","","","","","","","","","2016-10-06","2016-10-06","2017-11-30","","","20","","1","","","","","","true","","","" "1046389","Brodin, G. (Umeå University, Sweden);Stenflo, Lennart [lenst65] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","A new decay channel for upper-hybrid waves","Artikel i tidskrift","Refereegranskat","eng","Physica Scripta","0031-8949","1402-4896","published","91","10","","","","2016","","","","IOP PUBLISHING LTD","","","","","","","10.1088/0031-8949/91/10/104005","000385519200002","","","urn:nbn:se:liu:diva-132533","","","upper-hybrid waves; three-wave interaction; electrostatic fields","Fusion, plasma och rymdfysik (10303)","","","","<p>We look here at a three-wave interaction process involving only electrostatic waves in an electron plasma with stationary ions. Special attention is given to the case with an upper-hybrid wave as a pump wave, where a new decay channel is pointed out. The corresponding growth rate is calculated.</p>","","","","","","","","","","","","","2016-11-13","2016-11-14","2017-11-29","","","2","","1","","","","","104005","false","","","" "1046284","Sidnov, K. P. (National University of Science and Technology MISIS, Russia; RAS, Russia);Belov, D. S. (National University of Science and Technology MISIS, Russia);Ponomareva, A. V. (National University of Science and Technology MISIS, Russia);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Zharmukhambetova, A. M. (National Research Tomsk State University, Russia);Skripnyak, Natalia [natsk33] [0000-0003-1634-5882] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (National Research Tomsk State University, Russia);Barannikova, S. A. (National Research Tomsk State University, Russia; RAS, Russia);Rogachev, A. S. (National University of Science and Technology MISIS, Russia; RAS, Russia);Rouvimov, S. (University of Notre Dame, IN 46556 USA);Mukasyan, A. S. (University of Notre Dame, IN 46556 USA)","Effect of alloying on elastic properties of ternary Ni-Al-Ti system: Experimental validation","Artikel i tidskrift","Refereegranskat","eng","Journal of Alloys and Compounds","0925-8388","1873-4669","published","688","","","534","541","2016","","","","ELSEVIER SCIENCE SA","","","","","","","10.1016/j.jallcom.2016.07.051","000384430800070","","","urn:nbn:se:liu:diva-132464","","","Combustion synthesis; NiAl-based superalloys; Ti doping; Module of elasticity; First-principles simulations; Ductility","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Ministry of Education and Science of the Russian Federation [14.Y26.31.0005, K2-2014-001]; Tomsk State University Academic D. I. Mendeleev Fund Program [8.1.18.2015]; Swedish Foundation for Strategic Research (SSF) program SRL Grant [10-0026]; Swedish Research Council (VR) [2015-04391]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]; Russian Foundation for Basic Researches [16-02-00797 a]</p>","<p>Using combustion synthesis approach we fabricated B2 NiAl intermetallic compound as well as quasibinary Ni(Al50Ti50) alloy, where half Al atoms are randomly substituted by transitional metal Ti. Youngs modulus for synthesized materials was measured and appeared to be 222 +/- 10 GPa for NiAl and 175 +/- 15 GPa for Ni(Al50Ti50) phases. Using first-principles simulations in the framework of the Density Functional Theory, we investigate the elastic properties of Ni(Al1-xTix) system, including single-crystal, as well as polycrystalline elastic moduli. Direct comparison of the experimental and theoretical values of the Youngs modulus demonstrates that the employed theoretical approach allows carefully predict elastic properties of NiAl-based intermetallics. In particular, we predict that alloying NiAl with Ti should increase the ductility of the intermetallic phase. (C) 2016 Elsevier B.V. All rights reserved.</p>","","","","","","","","","","","","","2016-11-12","2016-11-13","2017-11-29","","","10","","1","","","","","","false","","","" "1034924","Schoeneberg, Johannes (University of Kiel, Germany);Caffrey, Nuala Mai [nuaca84] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Kiel, Germany);Ferriani, Paolo (University of Kiel, Germany);Heinze, Stefan (University of Kiel, Germany);Berndt, Richard (University of Kiel, Germany)","Distance- and spin-resolved spectroscopy of iridium atoms on an iron bilayer","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","94","11","","115418","","2016","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.94.115418","000383143200006","","","urn:nbn:se:liu:diva-131883","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Deutsche Forschungsgemeinschaft [SFB 677]; [SFB 668]</p>","<p>The induced spin polarization of Ir atoms on a ferromagnetic Fe double layer on W(110) has been investigated with spin-polarized scanning tunneling microscopy. An unoccupied state is observed with a spin polarization exceeding 60% that is inverted with respect to the Fe layer. This inversion is due to the tunneling gap acting as an orbital and spin filter. Distance dependent measurements show that the spin polarization remains approximately constant over the entire experimentally accessible range, from far in the tunneling regime to 1 angstrom from the point of contact formation. This is corroborated by density functional theory calculations which show that the inversion of spin polarization occurs within 0.5 angstrom of the adatom.</p>","","","","","","","","","","","","","2016-10-11","2016-10-13","2017-11-29","http://liu.diva-portal.org/smash/get/diva2:1034924/FULLTEXT01.pdf","","5","","0","","","","","","false","","","" "1034870","Nilsson, Johan O. (KTH Royal Institute Technology, Sweden);Leetmaa, Mikael (Uppsala University, Sweden);Vekilova, Olga Yu. (KTH Royal Institute Technology, Sweden);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Skorodumova, Natalia V. (KTH Royal Institute Technology, Sweden; Uppsala University, Sweden)","Statistical error in simulations of Poisson processes: Example of diffusion in solids","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","94","8","","","","2016","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.94.085206","000383030900005","","","urn:nbn:se:liu:diva-131903","","","","Teoretisk kemi (10407)","","","<p>Funding Agencies|Swedish Energy Agency (STEM) [35515-1]; Carl Tryggers Foundation [CTS 14:433]; Swedish Research Council (VR) [2014-5993, 2011-42-59]; LiLi-NFM; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-MatLiU) [2009 00971]</p>","<p>Simulations of diffusion in solids often produce poor statistics of diffusion events. We present an analytical expression for the statistical error in ion conductivity obtained in such simulations. The error expression is not restricted to any computational method in particular, but valid in the context of simulation of Poisson processes in general. This analytical error expression is verified numerically for the case of Gd-doped ceria by running a large number of kinetic Monte Carlo calculations.</p>","","","","","","","","","","","","","2016-10-11","2016-10-13","2017-11-29","http://liu.diva-portal.org/smash/get/diva2:1034870/FULLTEXT01.pdf","","5","","0","","","","","085206","false","","","" "1038466","Delange, Pascal (University of Paris Saclay, France);Ayral, Thomas (CEA, France);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Ferrero, Michel (University of Paris Saclay, France; Coll France, France);Parcollet, Olivier (CEA, France);Biermann, Silke (University of Paris Saclay, France; Coll France, France);Pourovskii, Leonid (University of Paris Saclay, France; Coll France, France; National University of Science and Technology MISIS, Russia)","Large effects of subtle electronic correlations on the energetics of vacancies in alpha-Fe","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","94","10","","100102","","2016","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.94.100102","000383859300001","","","urn:nbn:se:liu:diva-132054","","","","Teoretisk kemi (10407)","","","<p>Funding Agencies|Ministry of Education and Science of the Russian Federation; Swedish Research Council (VR) [2014-4750]; LiLi-NFM; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]; FP7/ERC [278472-MottMetals]; IDRIS/GENCI Orsay [t2016091393]; European Research Council under the European Unions Seventh Framework Programme/ERC Grant [617196, 319286]; Increase Competitiveness Program of NUST MISiS [K2-2016-013]</p>","<p>We study the effect of electronic Coulomb correlations on the vacancy formation energy in paramagnetic alpha-Fe within ab initio dynamical mean-field theory. The calculated value for the formation energy is substantially lower than in standard density-functional calculations and in excellent agreement with experiment. The reduction is caused by an enhancement of electronic correlations at the nearest neighbors of the vacancy. This effect is explained by subtle changes in the corresponding spectral function of the d electrons. The local lattice relaxations around the vacancy are substantially increased by many-body effects.</p>","","","","","","","","","","","","","2016-10-17","2016-10-18","2017-11-29","http://liu.diva-portal.org/smash/get/diva2:1038466/FULLTEXT01.pdf","","7","","0","","","","","","false","","","" "1034838","Rastgoo-Lahrood, Atena (Technical University of Munich, Germany; Deutsch Museum, Germany; Nanosyst Initiat Munich, Germany; Centre Nanosci, Germany);Björk, Jonas [jonbj66] [0000-0002-1345-0006] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Lischka, Matthias (Technical University of Munich, Germany; Deutsch Museum, Germany; Nanosyst Initiat Munich, Germany; Centre Nanosci, Germany);Eichhorn, Johanna (Technical University of Munich, Germany; Deutsch Museum, Germany; Nanosyst Initiat Munich, Germany; Centre Nanosci, Germany);Kloft, Stephan (Technical University of Munich, Germany; Deutsch Museum, Germany; Nanosyst Initiat Munich, Germany; Centre Nanosci, Germany);Fritton, Massimo (Technical University of Munich, Germany; Deutsch Museum, Germany; Nanosyst Initiat Munich, Germany; Centre Nanosci, Germany);Strunskus, Thomas (University of Kiel, Germany);Samanta, Debabrata (University of Siegen, Germany);Schmittel, Michael (University of Siegen, Germany);Heckl, Wolfgang M. (Technical University of Munich, Germany; Deutsch Museum, Germany; Nanosyst Initiat Munich, Germany; Centre Nanosci, Germany);Lackinger, Markus (Technical University of Munich, Germany; Deutsch Museum, Germany; Nanosyst Initiat Munich, Germany; Centre Nanosci, Germany)","Post-Synthetic Decoupling of On-Surface-Synthesized Covalent Nanostructures from Ag(111)","Artikel i tidskrift","Refereegranskat","eng","Angewandte Chemie International Edition","1433-7851","1521-3773","published","55","27","","7650","7654","2016","","","","WILEY-V C H VERLAG GMBH","","","","","","","10.1002/anie.201600684","000383252900006","27125328","","urn:nbn:se:liu:diva-131915","","","covalent networks; decoupling; surface chemistry; scanning probe microscopy; X-ray absorption spectroscopy","Materialkemi (10403)","","","<p>Funding Agencies|DFG [LA1842/4-1]; Nanosystems Initiative Munich; Helmholtz-Zentrum Berlin</p>","<p>The on-surface synthesis of covalent organic nanosheets driven by reactive metal surfaces leads to strongly adsorbed organic nanostructures, which conceals their intrinsic properties. Hence, reducing the electronic coupling between the organic networks and commonly used metal surfaces is an important step towards characterization of the true material. We demonstrate that post-synthetic exposure to iodine vapor leads to the intercalation of an iodine monolayer between covalent polyphenylene networks and Ag(111) surfaces. The experimentally observed changes from surface-bound to detached nanosheets are reproduced by DFT simulations. These findings suggest that the intercalation of iodine provides a material that shows geometric and electronic properties substantially closer to those of the freestanding network.</p>","","","","","","","","","","","","","2016-10-11","2016-10-13","2017-11-29","","","11","","2","","","","","","false","","","" "1040091","Burakovsky, L. (Los Alamos National Lab, NM 87545 USA);Burakovsky, N. (Los Alamos National Lab, NM 87545 USA);Cawkwell, M. J. (Los Alamos National Lab, NM 87545 USA);Preston, D. L. (Los Alamos National Lab, NM 87545 USA);Errandonea, D. (University of Valencia, Spain);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Ab initio phase diagram of iridium","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","94","9","","094112","","2016","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.94.094112","000384064800001","","","urn:nbn:se:liu:diva-132214","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|US DOE/NNSA; Spanish MINECO [MAT2013-46649-C4-1-P, MAT2015-71070-REDC]</p>","<p>The phase diagram of iridium is investigated using the Z methodology. The Z methodology is a technique for phase diagram studies that combines the direct Z method for the computation of melting curves and the inverse Z method for the calculation of solid-solid phase boundaries. In the direct Z method, the solid phases along the melting curve are determined by comparing the solid-liquid equilibrium boundaries of candidate crystal structures. The inverse Z method involves quenching the liquid into the most stable solid phase at various temperatures and pressures to locate a solid-solid boundary. Although excellent agreement with the available experimental data (to less than or similar to 65 GPa) is found for the equation of state (EOS) of Ir, it is the third-order Birch-Murnaghan EOS with B-0 = 5 rather than the more widely accepted B-0 = 4 that describes our ab initio data to higher pressure (P). Our results suggest the existence of a random-stacking hexagonal close-packed structure of iridium at high P. We offer an explanation for the 14-layer hexagonal structure observed in experiments by Cerenius and Dubrovinsky.</p>","","","","","","","","","","","","","2016-10-21","2016-10-26","2017-11-29","http://liu.diva-portal.org/smash/get/diva2:1040091/FULLTEXT01.pdf","","6","","0","","","","","","false","","","" "1010238","Stenflo, Lennart [lenst65] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Brodin, G. (Umeå University, Sweden)","Temperature effects on large amplitude electron plasma oscillations","Artikel i tidskrift","Refereegranskat","eng","Physics of Plasmas","1070-664X","1089-7674","published","23","7","","","","2016","","","","AMER INST PHYSICS","","","","","","","10.1063/1.4955325","000382447800106","","","urn:nbn:se:liu:diva-131715","","","","Fusion, plasma och rymdfysik (10303)","","","","<p>We present a very simple model equation that can describe one-dimensional large amplitude electron plasma oscillations. Published by AIP Publishing.</p>","","","","","","","","","","","","","2016-09-30","2016-10-03","2017-11-30","","","2","","1","","","","","074501","false","","","" "1010181","Björk, Jonas [jonbj66] [0000-0002-1345-0006] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk kemi [16855]) (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Linköping University)","Thermodynamics of an Electrocyclic Ring-Closure Reaction on Au(111)","Artikel i tidskrift","Refereegranskat","eng","The Journal of Physical Chemistry C","1932-7447","1932-7455","published","120","38","","21716","21721","2016","","","","American Chemical Society (ACS)","","","","","","","10.1021/acs.jpcc.6b08755","000384626800063","","","urn:nbn:se:liu:diva-131752","","","","Fysikalisk kemi (10402);Teoretisk kemi (10407)","","","","<p>We have computationally studied the effects of temperature on the reaction pathway of an electrocyclic ring-closure reaction on the Au(111) surface, particularly focusing on thermodynamic aspects of the reaction. The electrocyclic ring closure is accompanied by a series of dehydrogenation steps, and while it is found that temperature, in terms of vibrational entropy and enthalpy, has a reducing effect on most energy barriers, it does not alter the qualitative appreciation of the reaction kinetics. However, it is found that the way the abstracted hydrogen atoms are treated is crucial for the thermodynamics of the reaction. The overall reaction is highly endothermic but becomes thermodynamically favorable due to the entropy gain of the hydrogen byproducts, which desorb associatively from the surface as H2. The study provides new outlooks for the theoretical treatment of reactions related to on-surface synthesis, anticipated to be instructive for future studies.</p>","","","","","","","","","","","","","2016-10-03","2016-10-03","2017-11-30","http://liu.diva-portal.org/smash/get/diva2:1010181/FULLTEXT01.pdf","","1","","1","","","","","","true","","","" "1007210","Mei, A. B. (University of Illinois, IL 61801 USA);Tuteja, M. (University of Illinois, IL 61801 USA; University of Illinois, IL 61801 USA);Sangiovanni, Davide [davsa82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Haasch, R. T. (University of Illinois, IL 61801 USA; University of Illinois, IL 61801 USA);Rockett, A. (University of Illinois, IL 61801 USA);Hultman, Lars [larhu75] [0000-0002-2837-3656] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Petrov, Ivan [ivape26] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Illinois, IL 61801 USA);Greene, Joseph E [josgr17] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Illinois, IL 61801 USA)","Growth, nanostructure, and optical properties of epitaxial VNx/MgO(001) (0.80 &lt;= x &lt;= 1.00) layers deposited by reactive magnetron sputtering","Artikel i tidskrift","Refereegranskat","eng","Journal of Materials Chemistry C","2050-7526","2050-7534","published","4","34","","7924","7938","2016","","","","ROYAL SOC CHEMISTRY","","","","","","","10.1039/c6tc02289h","000382064100004","","","urn:nbn:se:liu:diva-131728","","","","Atom- och molekylfysik och optik (10302)","","","<p>Funding Agencies|Swedish Research Council (VR) program [637-2013-7296, 2014-5790, 2013-4018]; Swedish Government Strategic Research Area Grant in Materials Science on Advanced Functional Materials [SFO Mat-LiU 2009-00971]; Wallenberg Scholar Grant [KAW 2011.0143]</p>","<p>VNx/MgO(001) films, similar to 300 nm thick, with x ranging from 1.00 (stoichiometric) to 0.80 are grown by magnetically-unbalanced reactive magnetron sputter deposition in mixed N-2/Ar atmospheres. The combination of lattice-resolution cross-sectional electron microscopy with X-ray diffraction omega = 2 theta, phi-scans, pole figures, and high resolution reciprocal space maps show that VNx layers are epitaxial single crystals which grow cube-on-cube with respect to their substrates: (001)VNx vertical bar vertical bar (001)(MgO) and [100]VNx vertical bar vertical bar [100](MgO). VNx (001) relaxed lattice parameters a(0)(x) decrease linearly from 0.4134 (x = 1.00) to 0.4098 nm (x = 0.80), in agreement with density functional theory (DFT) calculations. Near-stoichiometric VNx layers (0.95 less than or similar to x less than or similar to 1.0) are fully relaxed during growth, while films with lower x values are partially strained as a result of increased anion vacancies impeding dislocation glide. VNx complex dielectric functions epsilon((h) over bar omega) are determined between 0.7 and 4.5 eV using variable-angle spectroscopic ellipsometry and valence states are probed via ultraviolet photoelectron spectroscopy (UPS) in concert with DFT calculations. VN(001) UPS spectra exhibit a feature at binding energies ranging from the Fermi level to 3 eV, together with two peaks deeper in the valence band. These results are consistent with electronic densities of states computed by scaling Kohn-Sham electronic eigenvalues to account for many-body interactions. Imaginary VN(001) dielectric functions epsilon((h) over bar omega) determined by ellipsometry also agree with theoretical values obtained within the random-phase approximation using scaled eigenvalues. Analyses of optical matrix element calculations reveal that VNx dielectric responses are controlled by the phase space for interband transitions; band-structure analyses indicate that epsilon(2)(amp;lt;(hover baramp;gt;omega) spectral features in the infrared-visible range arise primarily from the combination of intraband and d-d transitions, while features at higher energies result primarily from p-d interband transitions. The combined nanostructural and spectroscopic analyses establish that, surprisingly, N vacancies are essentially non-nteracting in high-quality epitaxial VNx containing vacancy concentrations up to similar to 10(22) cm(-3) (x = 0.80).</p>","","","","","","","","","","","","","2016-09-30","2016-09-30","2017-11-30","","","8","","1","","","","","","false","","","" "899814","Dahlqvist, Martin [marda09] [0000-0001-5036-2833] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Ingason, Arni Sigurdur [arnin42] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Magnus, F. (Uppsala University, Sweden);Thore, Andreas [andth13] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Petruhins, Andrejs [andpe38] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Mockuté, Aurelija [aurmo58] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Arnalds, U. B. (University of Iceland, Iceland);Sahlberg, M. (Uppsala University, Sweden);Hjorvarsson, B. (Uppsala University, Sweden);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (National University of Science and Technology MISIS, Russia; Tomsk State University, Russia);Rosén, Johanna [johro07] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Magnetically driven anisotropic structural changes in the atomic laminate Mn2GaC","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","93","1","","014410","","2016","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.93.014410","000367779000005","","","urn:nbn:se:liu:diva-124463","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|European Research Council under the European Communities Seventh Framework Programme (FP7)/ERC Grant [258509]; Swedish Research Council (VR) [642-2013-8020, 621-2011-4417]; KAW Fellowship program; SSF synergy grant FUNCASE; VR Grant [621-2011-4426]; Russian Federation Ministry for Science and Education [14.Y26.31.0005]; Tomsk State University Academic D. I. Mendeleev Fund Program</p>","<p>Inherently layered magnetic materials, such as magnetic M(n+1)AX(n) (MAX) phases, offer an intriguing perspective for use in spintronics applications and as ideal model systems for fundamental studies of complex magnetic phenomena. The MAX phase composition M(n+1)AX(n) consists of M(n+1)AX(n) blocks separated by atomically thin A-layers where M is a transition metal, A an A-group element, X refers to carbon and/or nitrogen, and n is typically 1, 2, or 3. Here, we show that the recently discovered magnetic Mn2GaC MAX phase displays structural changes linked to the magnetic anisotropy, and a rich magnetic phase diagram which can be manipulated through temperature and magnetic field. Using first-principles calculations and Monte Carlo simulations, an essentially one-dimensional (1D) interlayer plethora of two-dimensioanl (2D) Mn-C-Mn trilayers with robust intralayer ferromagnetic spin coupling was revealed. The complex transitions between them were observed to induce magnetically driven anisotropic structural changes. The magnetic behavior as well as structural changes dependent on the temperature and applied magnetic field are explained by the large number of low energy, i.e., close to degenerate, collinear and noncollinear spin configurations that become accessible to the system with a change in volume. These results indicate that the magnetic state can be directly controlled by an applied pressure or through the introduction of stress and show promise for the use of Mn2GaC MAX phases in future magnetoelectric and magnetocaloric applications.</p>","","","","","","","","","","","","","2016-02-01","2016-02-02","2017-11-30","http://liu.diva-portal.org/smash/get/diva2:899814/FULLTEXT01.pdf","","12","","0","","","","","","false","","","" "899816","Sangiovanni, Davide [davsa82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Hultman, Lars [larhu75] [0000-0002-2837-3656] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Chirita, Valeriu [valch35] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Petrov, Ivan [ivape26] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Illinois, USA);Greene, Joseph E [josgr17] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Illinois, USA)","Effects of phase stability, lattice ordering, and electron density on plastic deformation in cubic TiWN pseudobinary transition-metal nitride alloys","Artikel i tidskrift","Refereegranskat","eng","Acta Materialia","1359-6454","1873-2453","published","103","","","823","835","2016","","","","PERGAMON-ELSEVIER SCIENCE LTD","","","","","","","10.1016/j.actamat.2015.10.039","000367630500081","","","urn:nbn:se:liu:diva-124462","","","Nitrides; Toughness Phase stability; Density functional theory (DFT); Electronic structure","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Knut and Alice Wallenberg Foundation [2011.0094]; Swedish Research Council (VR) Linkoping Linnaeus Initiative LiLi-NFM [2008-6572, 2014-5790, 2013-4018]; Swedish Government Strategic Research Area Grant in Materials Science on Advanced Functional Materials through Swedens innovation agency VINNOVA [2009-00971]</p>","<p>We carry out density functional theory calculations to compare the energetics of layer glide, as well as stress vs. strain curves, for cubic Ti0.5W0.5N pseudobinary alloys and reference B1-structure TiN. Irrespective of the degree of ordering on the metal sublattice, the hardness and stiffness of Ti0.5W0.5, as estimated by stress strain results and resistance to layer glide, are comparable to that of the parent binary TiN, while ductility is considerably enhanced. After an initial elastic response to an applied load, the pseudobinary alloy deforms plastically, thus releasing accumulated mechanical stress. In contrast, stress continues to increase linearly with strain in TiN. Layer glide in Ti0.5W0.5N is promoted by a high valence-electron concentration which enables the formation of strong metallic bonds within the slip direction upon deformation. [1111-oriented Ti0.5W0.5N layers characterized by high local metal-sublattice ordering exhibit low resistance to slip along &amp;lt; 110 &amp;gt; directions due to energetically favored formation of (111) hexagonal stacking faults. This is consistent with the positive formation energy of &amp;lt; 111 &amp;gt;-ordered Tio.5W0.5N with respect to mixing of cubic-BI TiN and hexagonal WC-structure WN. In the cubic pseudobinary alloy, slip occurs parallel, as well as orthogonal, to the resolved applied stress at the interface between layers with the lowest friction. We suggest that analogous structural metastability (mixing cubic and hexagonal TM nitride binary phases) and electronic (high valence electron concentration) effects are responsible for the enhanced toughness recently demonstrated experimentally for cubic single-crystal pseudobinary V0.5W0.5N and V0.5MocoN epitaxial layers. (c) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.</p>","","","","","","","","","","","","","2016-02-01","2016-02-02","2017-11-30","","","5","","2","","","","","","false","","","" "899805","Nilsson, Johan O. (KTH Royal Institute Technology, Sweden);Yu Vekilova, Olga (KTH Royal Institute Technology, Sweden);Hellman, Olle [olohe96] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Klarbring, Johan [johkl85] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Skorodumova, Natalia V. (KTH Royal Institute Technology, Sweden; Uppsala University, Sweden)","Ionic conductivity in Gd-doped CeO2: Ab initio color-diffusion nonequilibrium molecular dynamics study","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","93","2","","024102","","2016","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.93.024102","000367662100002","","","urn:nbn:se:liu:diva-124465","","","","Fysik (103)","","","<p>Funding Agencies|Swedish Energy Agency (STEM) [355151]; Carl Tryggers Foundation [CTS 14:433]; Swedish Research Council (VR) [2014-5993, 2014-4750, 637-2013-7296]; LiLi-NFM; Swedish Government Strategic Research Area Grant in Materials Science</p>","<p>A first-principles nonequilibrium molecular dynamics (NEMD) study employing the color-diffusion algorithm has been conducted to obtain the bulk ionic conductivity and the diffusion constant of gadolinium-doped cerium oxide (GDC) in the 850-1150 K temperature range. Being a slow process, ionic diffusion in solids usually requires simulation times that are prohibitively long for ab initio equilibrium molecular dynamics. The use of the color-diffusion algorithm allowed us to substantially speed up the oxygen-ion diffusion. The key parameters of the method, such as field direction and strength as well as color-charge distribution, have been investigated and their optimized values for the considered system have been determined. The calculated ionic conductivity and diffusion constants are in good agreement with available experimental data.</p>","","","","","","","","","","","","","2016-02-01","2016-02-02","2017-11-30","http://liu.diva-portal.org/smash/get/diva2:899805/FULLTEXT01.pdf","","6","","0","","","","","","false","","","" "921609","Finzel, Kati [katfi97] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Reinvestigation of the ideal atomic shell structure and its application in orbital-free density functional theory","Artikel i tidskrift","Refereegranskat","eng","Theoretical Chemistry accounts","1432-881X","1432-2234","published","135","4","","87","","2016","","","","SPRINGER","","","","","","","10.1007/s00214-016-1850-8","000372751800002","","","urn:nbn:se:liu:diva-127271","","","Atomic shell structure; Pauli potential; Orbital-free DFT; Atoms","Fysik (103)","","","<p>Funding Agencies|Alexander von Humboldt foundation</p>","<p>It is shown how to determine the ideal shell radii solely as a function of the nuclear charge. With the help of those ideal shell radii, an approximation to the Pauli potential for atoms in their groundstate can be constructed. The so-called SSB-ideal potential (shell structure-based) yields self-consistent orbital-free electron densities with proper atomic shell structure from Hohenberg-Kohn variational principle.</p>","","","","","","","","","","","","","2016-04-19","2016-04-20","2017-11-30","","","1","","1","","","","","","false","","","" "910063","Tholander, Christopher [chrth86] [0000-0001-6914-9354] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Birch, Jens [jenbi91] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Tasnádi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Hultman, Lars [larhu75] [0000-0002-2837-3656] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Palisaitis, Justinas [juspa01] [0000-0003-3203-7935] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Persson, Per O A [perpe25] [0000-0001-9140-6724] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Jensen, Jens [jenje80] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Sandström, Per [persa20] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, Germany);Zukauskaitè, Agne [agnzu70] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Fraunhofer Institute for Applied Solid State Physics IAF, Freiburg, Germany)","Ab initio calculations and experimental study of piezoelectric Y_xIn_1-xN thin films deposited using reactive magnetron sputter epitaxy","Artikel i tidskrift","Refereegranskat","eng","Acta Materialia","1359-6454","1873-2453","published","105","","","199","206","2016","","","","Elsevier","","","","","","","10.1016/j.actamat.2015.11.050","000370086500023","","","urn:nbn:se:liu:diva-125918","","","YInN;Thin films;Sputter deposition;Piezoelectricity;Ab initio calculations","Den kondenserade materiens fysik (10304);Materialkemi (10403);Oorganisk kemi (10404);Annan materialteknik (20599);Bearbetnings-, yt- och fogningsteknik (20505)","","","","<p>By combining theoretical prediction and experimental verification we investigate the piezoelectric properties of yttrium indium nitride (Y_xIn_1-xN). Ab initio calculations show that the Y_xIn_1-xN wurtzite phase is lowest in energy among relevant alloy structures for 0≤x≤0.5. Reactive magnetron sputter epitaxy was used to prepare thin films with Y content up to x=0.51. The composition dependence of the lattice parameters observed in the grown films is in agreement with that predicted by the theoretical calculations confirming the possibility to synthesize a wurtzite solid solution. An AlN buffer layer greatly improves the crystalline quality and surface morphology of subsequently grown Y_xIn_1-xN films. The piezoelectric response in films with x=0.09 and x=0.14 is observed using piezoresponse force microscopy. Theoretical calculations of the piezoelectric properties predict YxIn1−xN to have comparable piezoelectric properties to Sc_xAl_1-xN.</p>","","","","","","","","","","","","","2016-03-08","2016-03-08","2017-11-30","","","10","","2","urn:nbn:se:liu:diva-125919","","","","","true","","","" "909029","Yakimenko, Irina I. [iryya88] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Berggren, Karl-Fredrik [karbe79] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Probing dopants in wide semiconductorquantum point contacts","Artikel i tidskrift","Refereegranskat","eng","Journal of Physics: Condensed Matter","0953-8984","1361-648X","published","28","10","","1","10","2016","","","","Institute of Physics (IOP)","","","","","","","10.1088/0953-8984/28/10/105801","000371007800014","26885626","","urn:nbn:se:liu:diva-125790","","","","Den kondenserade materiens fysik (10304);Annan fysik (10399)","","","<p>Funding agencies: Carl Trygger Science Foundation of Sweden [CTS: 13-519]; National Supercomputer Centre at Linkoping University, Sweden</p>","<p>Effects of randomly distributed impurities on conductance, spin polarization and electronlocalization in realistic gated semiconductor quantum point contacts (QPCs) have beensimulated numerically. To this end density functional theory in the local spin-densityapproximation has been used. In the case when the donor layer is embedded far from thetwo-dimensional electron gas (2DEG) the electrostatic confinement potential exhibits theconventional parabolic form, and thus the usual ballistic transport phenomena take place bothin the devices with split gates alone and with an additional metallic gate on the top.In the opposite case, i.e. when the randomly distributed donors are placed not far away fromthe 2DEG layer, there are drastic changes like the localization of electrons in the vicinity ofconfinement potential minima which give rise to fluctuations in conductance and resonances.The conductance as a function of the voltage applied to the top gate for asymmetricallycharged split gates has been calculated. In this case resonances in conductance caused byrandomly distributed donors are shifted and decrease in amplitude while the anomaliescaused by interaction effects remain unmodified. It has been also shown that for a wide QPCthe polarization can appear in the form of stripes. The importance of partial ionization ofthe random donors and the possibility of short range order among the ionized donors areemphasized. The motivation for this work is to critically evaluate the nature of impurities andhow to guide the design of high-mobility devices.</p>","","","","","","","","","","","","","2016-03-04","2016-03-04","2017-11-30","http://liu.diva-portal.org/smash/get/diva2:909029/FULLTEXT01.pdf","","2","","1","","","","","105801","false","","","" "908209","Jason, Peter [petja31] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Johansson, Magnus [magjo23] [0000-0001-6708-1560] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Discrete breathers for a discrete nonlinear Schrodinger ring coupled to a central site","Artikel i tidskrift","Refereegranskat","eng","Physical Review E. Statistical, Nonlinear, and Soft Matter Physics: Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics","1063-651X","1095-3787","published","93","1","","012219","","2016","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevE.93.012219","000369333600003","26871085","","urn:nbn:se:liu:diva-125683","","","","Fysik (103)","","","","<p>We examine the existence and properties of certain discrete breathers for a discrete nonlinear Schrodinger model where all but one site are placed in a ring and coupled to the additional central site. The discrete breathers we focus on are stationary solutions mainly localized on one or a few of the ring sites and possibly also the central site. By numerical methods, we trace out and study the continuous families the discrete breathers belong to. Our main result is the discovery of a split bifurcation at a critical value of the coupling between neighboring ring sites. Below this critical value, families form closed loops in a certain parameter space, implying that discrete breathers with and without central-site occupation belong to the same family. Above the split bifurcation the families split up into several separate ones, which bifurcate with solutions with constant ring amplitudes. For symmetry reasons, the families have different properties below the split bifurcation for even and odd numbers of sites. It is also determined under which conditions the discrete breathers are linearly stable. The dynamics of some simpler initial conditions that approximate the discrete breathers are also studied and the parameter regimes where the dynamics remain localized close to the initially excited ring site are related to the linear stability of the exact discrete breathers.</p>","","","","","","","","","","","","","2016-02-29","2016-03-01","2017-11-30","","","2","","0","urn:nbn:se:liu:diva-129564","","","","","false","","","" "875192","Shulumba, Nina [ninsh46] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Saarland, Germany);Raza, Zamaan [zamra51] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Hellman, Olle [olohe96] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Division of Engineering and Applied Science, California Institute of Technology, Pasadena, California, USA);Janzén, Erik [erija14] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Materials Modeling and Development Laboratory, NUST “MISIS”, Moscow, Russia; LACOMAS Laboratory, Tomsk State University, Tomsk, Russia);Odén, Magnus [magod41] [0000-0002-2286-5588] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Impact of anharmonic effects on the phase stability, thermal transport, and electronic properties of AlN","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","94","10","","","","2016","","","","","","","","","","","10.1103/PhysRevB.94.104305","000384061100003","","","urn:nbn:se:liu:diva-122955","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding agencies; Swedish Research Council (VR programs) [2015-04391, 621-2012-4401]; Swedish Foundation for Strategic Research (SSF program) [SRL10-0026]; VINNOVA [M-Era.net Project] [2013-02355 (MC2)]; Swedish Research Council VR program [637-2013-7296]; Swedish Foundati</p>","<p>Wurtzite aluminium nitride is a technologically important wide band gap semiconductor with an unusually high thermal conductivity, used in optical applications and as a heatsink substrate. Many of its properties depend on an accurate description of its lattice dynamics, which have thus far only been captured in the quasiharmonic approximation. In this work, we demonstrate that anharmonicity has a considerable impact on its phase stability and transport properties, since anharmonicity is much stronger in the rocksalt phase. We compute a pressure-temperature phase diagram of AlN, demonstrating that the rocksalt phase is stabilised by increasing temperature, with respect to the wurtzite phase. We demonstrate that including anharmonicity, we can recover the thermal conductivity of the wurtzite phase (320 Wm⁻¹K⁻¹ under ambient conditions), and compute the hitherto unknown thermal conductivity of the rocksalt phase (96 Wm⁻¹K⁻¹). We also show that the electronic band gap decreases with temperature. These findings provide further evidence that anharmonic effects cannot be ignored in high temperature applications.</p>","","","","","","","","","","","","","2015-11-30","2015-11-30","2017-12-01","","","6","","0","urn:nbn:se:liu:diva-122949","","","","104305","true","","","" "1035688","Finzel, Kati [katfi97] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Davidsson, Joel [joeda01] [0000-0002-5349-3318] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Energy-Surfaces from the Upper Bound of the Pauli Kinetic Energy","Artikel i tidskrift","Refereegranskat","eng","International Journal of Quantum Chemistry","0020-7608","1097-461X","published","116","18","","1337","1341","2016","","","","WILEY-BLACKWELL","","","","","","","10.1002/qua.25181","000383286100002","","","urn:nbn:se:liu:diva-131881","","","Pauli potential; Pauli kinetic energy; orbital-free density functional approximations","Teoretisk kemi (10407)","","","<p>Funding Agencies|Alexander von Humboldt foundation; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]; Swedish Government Strategic Research Area SeRC; Swedish Foundation for Strategic Research (SSF) program SRL [10-0026]</p>","<p>Based on the Kohn-Sham Pauli potential and the Kohn-Sham electron density, the upper bound of the Pauli kinetic energy is tested as a suitable replacement for the exact Pauli kinetic energy for application in orbital-free density functional calculations. It is found that bond lengths for strong and moderately bound systems can be qualitatively predicted, but with a systematic shift toward larger bond distances with a relative error of 6% up to 30%. Angular dependence of the energy-surface cannot be modeled with the proposed functional. Therefore, the upper bound model is the first parameter-free functional expression for the kinetic energy that is able to qualitatively reproduce binding curves with respect to bond distortions. (C) 2016 Wiley Periodicals, Inc.</p>","","","","","","","","","","","","","2016-10-11","2016-10-13","2018-01-25","","","3","","1","","","","","","false","","","" "1052474","Yalamanchili, Phani Kumar [sivya87] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Wang, Fei [feiwa67] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Saarland, Germany);Aboulfadl, Hisham (University of Saarland, Germany);Barrirero, Jenifer [jenba07] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Saarland, Germany);Rogström, Lina [linro82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Jimenez-Pique, Emilio (University of Politecn Cataluna, Spain; CRnE UPC, Spain);Muecklich, Frank (University of Saarland, Germany);Tasnadi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Odén, Magnus [magod41] [0000-0002-2286-5588] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Ghafoor, Naureen [naugh16] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Growth and thermal stability of TiN/ZrAlN: Effect of internal interfaces","Artikel i tidskrift","Refereegranskat","eng","Acta Materialia","1359-6454","1873-2453","published","121","","","396","406","2016","","","","Pergamon Press","","","","","","","10.1016/j.actamat.2016.07.006","000386984500038","","","urn:nbn:se:liu:diva-132827","","","Thermal stability;TM-Al-N multilayer films;Nanostructured materials;Interface energy;Three-dimensional atom probe (3DAP);Transmission electron microscopy","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Research Council (VR grant) [621-2012-4401]; Swedish Foundation for Strategic Research (SSF) through the program MultiFilms [RMA08-0069]; Swedish government strategic research area grant in material science AFM - SFO MatLiU [2009-00971]; EUs Erasmus Mundus graduate school in Material Science and Engineering (DocMASE); Swedish Governmental Agency for Innovation Systems [VINNMer 2011-03464, 2013-02355]; EU-funded project AME-Lab (European Regional Development Fund) [C/4-EFRE-13/2009/Br]; DFG; federal state government of Saarland [INST 256/298-1 FUGG]</p>","<p>Wear resistant hard films comprised of cubic transition metal nitride (c-TMN) and metastable c-AlN with coherent interfaces have a confined operating envelope governed by the limited thermal stability of metastable phases. However, equilibrium phases (c-TMN and wurtzite(w)-AlN) forming semicoherent interfaces during film growth offer higher thermal stability. We demonstrate this concept for a model multilayer system with TiN and ZrAlN layers where the latter is a nanocomposite of ZrN- and AlN-rich domains. The interfaces between the domains are tuned by changing the AlN crystal structure by varying the multilayer architecture and growth temperature. The interface energy minimization at higher growth temperature leads to formation of semicoherent interfaces between w-AlN and c-TMN during growth of 15 nm thin layers. Ab initio calculations predict higher thermodynamic stability of semicoherent interfaces between c-TMN and w-AlN than isostructural coherent interfaces between c-TMN and c-AlN. The combination of a stable interface structure and confinement of w-AlN to nm-sized domains by its low solubility in c-TMN in a multilayer, results in films with a stable hardness of 34 GPa even after annealing at 1150 degrees C. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.</p>","","","","","","","","","","","","","2016-11-30","2016-12-06","2018-02-09","","","10","","2","urn:nbn:se:liu:diva-145091","","","","","false","","","" "936024","Wang, Fei [feiwa67] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Saarland, Germany);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (NUST MISIS, Russia; Tomsk State University, Russia);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Odén, Magnus [magod41] [0000-0002-2286-5588] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Muecklich, Frank (University of Saarland, Germany);Tasnadi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Coherency effects on the mixing thermodynamics of cubic Ti1-xAlxN/TiN(001) multilayers","Artikel i tidskrift","Refereegranskat","eng","PHYSICAL REVIEW B","2469-9950","","published","93","17","","174201","","2016","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.93.174201","000375990200003","","","urn:nbn:se:liu:diva-129166","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Foundation for Strategic Research (SSF) project SRL [10-0026]; Erasmus Mundus Joint European Doctoral Programme DocMASE; Multiscale computational-design of novel hard nanostructure coatings; Swedish Research Council (VR) [2015-04391, 621-2012-4401, 2014-4750]; Grant of Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Tomsk State University Academic D. I. Mendeleev Fund Program [8.1.18.2015]; LiLi-NFM; Swedish Government Strategic Research Area Grant in Materials Science</p>","<p>In this work, we discuss the mixing thermodynamics of cubic (B1) Ti1-xAlxN/TiN(001) multilayers. We show that interfacial effects suppress the mixing enthalpy compared to bulk Ti1-xAlxN. The strongest stabilization occurs for compositions in which the mixing enthalpy of bulk Ti1-xAlxN has its maximum. The effect is split into a strain and an interfacial (or chemical) contribution, and we show that both contributions are significant. An analysis of the local atomic structure reveals that the Ti atoms located in the interfacial layers relax significantly different from those in the other atomic layers of the multilayer. Considering the electronic structure of the studied system, we demonstrate that the lower Ti-site projected density of states at epsilon(F) in the Ti1-xAlxN/TiN multilayers compared to the corresponding monolithic bulk explains a decreased tendency toward decomposition.</p>","","","","","","","","","","","","","2016-06-13","2016-06-13","2018-02-09","http://liu.diva-portal.org/smash/get/diva2:936024/FULLTEXT01.pdf","","6","","0","urn:nbn:se:liu:diva-145091","","","","","false","","","" "1043957","Pilch, Iris [iripi77] [0000-0003-3767-225X] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Caillault, L. (University of Paris 11, France);Minea, T. (University of Paris 11, France);Helmersson, Ulf [ulfhe30] [0000-0002-1744-7322] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Plasma och beläggningsfysik [2225]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Tal, Alexey [aleta94] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (National University of Science and Technology MISIS, Russia);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (National University of Science and Technology MISIS, Russia);Münger, Peter [petmu26] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Brenning, Nils [nilbr83] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Plasma och beläggningsfysik [2225]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (KTH Royal Institute Technology, Sweden)","Nanoparticle growth by collection of ions: orbital motion limited theory and collision-enhanced collection","Artikel i tidskrift","Refereegranskat","eng","Journal of Physics D: Applied Physics","0022-3727","1361-6463","published","49","39","","395208","","2016","","","","IOP PUBLISHING LTD","","","","","","","10.1088/0022-3727/49/39/395208","000384239200004","","","urn:nbn:se:liu:diva-132204","","","nanoparticle synthesis; pulsed plasma; complex plasmas","Fusion, plasma och rymdfysik (10303)","","","<p>Funding Agencies|Knut and Alice Wallenberg foundation [2014.0276]; Swedish Research Council under Linkoping Linneaus Environment LiLi-NFM [2008-6572]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Increase Competitiveness Program of MISiS</p>","<p>The growth of nanoparticles in plasma is modeled for situations where the growth is mainly due to the collection of ions of the growth material. The model is based on the classical orbit motion limited (OML) theory with the addition of a collision-enhanced collection (CEC) of ions. The limits for this type of model are assessed with respect to three processes that are not included: evaporation of the growth material, electron field emission, and thermionic emission of electrons. It is found that both evaporation and thermionic emission can be disregarded below a temperature that depends on the nanoparticle material and on the plasma parameters; for copper in our high-density plasma this limit is about 1200 K. Electron field emission can be disregarded above a critical nanoparticle radius, in our case around 1.4 nm. The model is benchmarked, with good agreement, to the growth of copper nanoparticles from a radius of 5 nm-20 nm in a pulsed power hollow cathode discharge. Ion collection by collisions contributes with approximately 10% of the total current to particle growth, in spite of the fact that the collision mean free path is four orders of magnitude longer than the nanoparticle radius.</p>","","","","","","","","","","","","","2016-10-21","2016-11-01","2018-03-15","http://liu.diva-portal.org/smash/get/diva2:1043957/FULLTEXT01.pdf","","8","","1","urn:nbn:se:liu:diva-145684","","","","","false","","","" "1074395","Tholander, Christopher [chrth86] [0000-0001-6914-9354] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Andersson, C. B. A. (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Armiento, Rickard [ricar47] [0000-0002-5571-0814] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Tasnadi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Max Planck Institute Eisenforsch GmbH, Germany)","Strong piezoelectric response in stable TiZnN2, ZrZnN2, and HfZnN2 found by ab initio high-throughput approach","Artikel i tidskrift","Refereegranskat","eng","Journal of Applied Physics","0021-8979","1089-7550","published","120","22","","","","2016","","","","AMER INST PHYSICS","","","","","","","10.1063/1.4971248","000391535900016","","","urn:nbn:se:liu:diva-134499","","","","Oorganisk kemi (10404)","","","<p>Funding Agencies|Swedish e-Science Research Centre (SeRC); Linnaeus Environment at Linkoping on Nanoscale Functional Materials (LiLi-NFM) - Vetenskapsradet (VR); VR [621-2011-4417, 330-2014-6336]; Marie Sklodowska Curie Actions [INCA 600398]</p>","<p>The phase diagrams of the Ti-Zn-N, Zr-Zn-N, and Hf-Zn-N systems are determined using large-scale high-throughput density functional calculations. Thermodynamically stable ordered phases of TiZnN2, ZrZnN2, and HfZnN2 have been found to be promising candidates in piezoelectric devices/applications for energy harvesting. The identified stable phase of TiZnN2 is an ordered wurtzite superstructure, and the stable phases of ZrZnN2 and HfZnN2 have a layered structure with alternating tetrahedral ZnN and octahedral (Zr, Hf)N layers. All of the TMZnN2 (TM = Ti, Zn, Hf) structures exhibit electronic bandgaps and large piezoelectric constants, d(33)(TiZnN2) = 14.21; d(24)(ZrZnN2) = -26.15, and d(24)(HfZnN2) = -21.99 pC/N. The strong piezoelectric responses and their thermodynamical stability make materials with these phases promising candidates for piezoelectric applications. Published by AIP Publishing.</p>","","","","","","","","","","","","","2017-02-15","2017-02-15","2018-03-19","","","5","","1","","","","","225102","false","","","" "934961","Tomita, Kota (University of Tokyo, Japan);Miyata, Tomohiro (University of Tokyo, Japan);Olovsson, Weine (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Mizoguchi, Teruyasu (University of Tokyo, Japan)","Core-Exciton Interaction in Sodium L-2,L-3 edge Structure Investigated Using the Bethe-Salpeter Equation","Artikel i tidskrift","Refereegranskat","eng","The Journal of Physical Chemistry C","1932-7447","1932-7455","published","120","17","","9036","9042","2016","","","","AMER CHEMICAL SOC","","","","","","","10.1021/acs.jpcc.5b12389","000375631100004","","","urn:nbn:se:liu:diva-128937","","","","Teoretisk kemi (10407)","","","<p>Funding Agencies|Ministry of Education, Culture, Sports, Science and Technology-Japan (MEXT) [25106003, 26630302, 26249092]; LiLi-NFM; Swedish Research Council (VR) [621-2011-4426]</p>","<p>Despite the importance of sodium compounds for their application in sodium-ion rechargeable batteries, core-exciton interactions in sodium L-2,L-3 edge core-electron loss spectra are not well-understood. In this study, Bethe-Salpeter equation calculations of sodium L-2,L-3 edges of sodium compounds were performed to understand the relationships between the core-exciton interactions and the electronic structure of sodium compounds. It was revealed that the core-exciton interaction of sodium compounds is strongly dependent on the compounds. We found that neither band gap nor ionic charge can explain the trend; however, the transition energy shows a clear correlation to the magnitude of the core-exciton interaction. These results indicate that the magnitude of the core-exciton interaction is decided by the excited electronic structure of each compound.</p>","","","","","","","","","","","","","2016-06-07","2016-06-09","2018-03-20","","","4","","1","","","","","","false","","","" "1054743","Caffrey, Nuala M. (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Armiento, Rickard [ricar47] [0000-0002-5571-0814] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Yakimova, Rositsa [rosia15] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (NUST MISIS, Russia; Tomsk State University, Russia)","Changes in work function due to NO2 adsorption on monolayer and bilayer epitaxial graphene on SiC(0001)","Artikel i tidskrift","Refereegranskat","eng","Physical Review B","2469-9950","2469-9969","published","94","20","","","","2016","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.94.205411","000387538400006","","","urn:nbn:se:liu:diva-132986","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|European Unions Horizon 2020 research and innovation programme [696656]; Swedish Research Council (VR) [621-2014-5805]; Swedish Foundation for Strategic Research (SSF) program SRL Grant [10-0026]; Swedish Government Strategic Research Area SeRC; Linnaeus Environment at Linkoping on Nanoscale Functional Materials (LiLi-NFM) - VR; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Tomsk State University Academic D. I. Mendeleev Fund Program [8.1.18.2015]</p>","<p>The electronic properties of monolayer graphene grown epitaxially on SiC(0001) are known to be highly sensitive to the presence of NO2 molecules. The presence of small areas of bilayer graphene, on the other hand, considerably reduces the overall sensitivity of the surface. We investigate how NO2 molecules interact with monolayer and bilayer graphene, both free-standing and on a SiC(0001) substrate. We show that it is necessary to explicitly include the effect of the substrate in order to reproduce the experimental results. When monolayer graphene is present on SiC, there is a large charge transfer from the interface between the buffer layer and the SiC substrate to the molecule. As a result, the surface work function increases by 0.9 eV after molecular adsorption. A graphene bilayer is more effective at screening this interfacial charge, and so the charge transfer and change in work function after NO2 adsorption is much smaller.</p>","","","","","","","","","","","","","2016-12-07","2016-12-09","2018-03-22","http://liu.diva-portal.org/smash/get/diva2:1054743/FULLTEXT01.pdf","","4","","2","","","","","205411","false","","","" "938938","Olovsson, Weine (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Max-Planck-Institut für Eisenforschung GmbH, D-402 37 Düsseldorf, Germany);Magnuson, Martin [marma66] [0000-0002-0317-0190] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Structure and Bonding in Amorphous Cr1−xCx Nanocomposite Thin Films: X‐ray Absorption Spectra and First-Principles Calculations","Artikel i tidskrift","Refereegranskat","eng","The Journal of Physical Chemistry C","1932-7447","1932-7455","published","120","23","","12890","12899","2016","","","","American Chemical Society (ACS)","","","","","https://arxiv.org/abs/1611.08540;https://people.ifm.liu.se/marma/;http://martinmagnuson.com/","","10.1021/acs.jpcc.6b03608","000378196200059","","","urn:nbn:se:liu:diva-129386","","","","Oorganisk kemi (10404);Teoretisk kemi (10407);Den kondenserade materiens fysik (10304)","","","<p>Funding agencies:We would like to thank the staff at MAX-lab for experimental support and U. Jansson and M. Andersson for providing the samples. This work was supported by the Swedish Research Council (VR) Linnaeus Grant LiLi-NFM, the FUNCASE project supported Swedish Strategic Research Foundation (SSF). W.O. acknowledges financial support from VR Grant No. 621-2011-4426, the Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU No 2009 00971), Knut and Alice Wallenbergs Foundation project Strong Field Physics and New States of Matter 2014-2019 (COTXS). B.A. would like to thank E. Holmstrom and R. Lizarraga for support with the SQ method and acknowledges financial support by the Swedish Research Council (VR) through the young researcher Grant No. 621-2011-4417 and the international career Grant No. 330-2014-6336 and Marie Sklodowska Curie Actions, Cofund, Project INCA 600398. The calculations were performed using supercomputer resources provided by the Swedish National Infrastructure for Computing (SNIC) at the National Supercomputer Centre (NSC) and Center for Parallel Computing (PDC).</p>","<p>The local structure and chemical bonding in two-phase amorphous Cr1−xCx nanocomposite thin films are investigated by Cr K-edge (1s) X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopies in comparison to theory. By utilizing the computationally efficient stochastic quenching (SQ) technique, we reveal the complexity of different Cr-sites in the transition metal carbides, highlighting the need for large scale averaging to obtain theoretical XANES and EXAFS spectra for comparison with measurements. As shown in this work, it is advantageous to use ab initio theory as an assessment to correctly model and fit experimental spectra and investigate the trends of bond lengths and coordination numbers in complex amorphous materials. With sufficient total carbon content (≥30 at. %), we find that the short-range coordination in the amorphous carbide phase exhibit similarities to that of a Cr7C3 ± y structure, while excessive carbons assemble in the amorphous carbon phase.</p>","","","","","","","","","","","","","2016-06-17","2016-06-17","2018-06-04","http://liu.diva-portal.org/smash/get/diva2:938938/FULLTEXT01.pdf","","3","","1","","","","","","true","","","" "866364","Ektarawong, Annop [annek02] [0000-0002-6059-6833] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Hultman, Lars [larhu75] [0000-0002-2837-3656] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Birch, Jens [jenbi91] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Tasnádi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Wang, Fei [feiwa67] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Max Planck Institute Eisenforsch GmbH, Germany)","Effects of configurational disorder on the elastic properties of icosahedral boron-rich alloys based on B₆O, B₁₃C₂, and B₄C, and their mixing thermodynamics","Artikel i tidskrift","Refereegranskat","eng","Journal of Chemical Physics","0021-9606","1089-7690","published","144","13","","","","2016","","","","American Institute of Physics (AIP)","","","","","","","10.1063/1.4944982","000374527900023","27059576","","urn:nbn:se:liu:diva-122425","","","","Fysik (103)","","","<p>Funding agencies:Swedish Research Council (VR) [621-2011-4417, 330-2014-6336, 2011-42-59]; CeNano at Linkoping University; Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of NUST ""MISiS"" [K3-2014-049]; LiLi-</p><p>At the time for thesis presentation publication was in status: Manuscript</p>","<p>The elastic properties of alloys between boron suboxide (B₆O) and boron carbide (B₁₃C₂), denoted by (B₆O)_1−x(B₁₃C₂)_x, as well as boron carbide with variable carbon content, ranging from B₁₃C₂ to B₄C are calculated from first-principles. Furthermore, the mixing thermodynamics of (B₆O)_1−x(B₁₃C₂)x is studied. A superatom-special quasirandom structure approach is used for modeling different atomic configurations, in which effects of configurational disorder between the carbide and suboxide structural units, as well as between boron and carbon atoms within the units, are taken into account. Elastic properties calculations demonstrate that configurational  disorder in B₁₃C₂, where a part of the C atoms in the CBC chains substitute for B atoms in the B12 icosahedra, drastically increase the Young’s and shear modulus, as compared to an atomically ordered state, B₁₂(CBC). These calculated elastic moduli of the disordered state are in excellent agreement with experiments. Configurational disorder between boron and carbon can also explain the experimentally observed almost constant elastic moduli of boron carbide as the carbon content is changed from B₄C to B₁₃C₂. The elastic moduli of the (B₆O)_1−x(B₁₃C₂)_x system are also practically unchanged with composition if boron-carbon disorder is taken into account. By investigating the mixing thermodynamics of the alloys, in which the Gibbs free energy is determined within the mean-field approximation for the configurational entropy, we outline the pseudo-binary phase diagram of (B₆O)_1−x(B₁₃C₂)_x. The phase diagram reveals the existence of a miscibility gap at all temperatures up to the melting point. Also, the coexistence of B₆O-rich as well as ordered or disordered B₁₃C₂-rich domains in the material prepared through equilibrium routes is predicted.</p>","","","","","","","","","","","","","2015-11-02","2015-11-02","2018-08-14","","","7","","1","urn:nbn:se:liu:diva-122426;urn:nbn:se:liu:diva-136813","","","","134503","true","","","" "974421","Ektarawong, Annop [annek02] [0000-0002-6059-6833] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Max Planck Institute Eisenforsch GmbH, Germany)","Carbon-rich icosahedral boron carbides beyond B4C and their thermodynamic stabilities at high temperature and pressure from first principles","Artikel i tidskrift","Refereegranskat","eng","PHYSICAL REVIEW B","2469-9950","2469-9969","published","94","5","","","","2016","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.94.054104","000381304300001","","","urn:nbn:se:liu:diva-131508","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Research Council (VR) [621-2011-4417, 330-2014-6336, 2014-4750]; Marie Sklodowska Curie Actions [INCA 600398]; CeNano at Linkoping University; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]</p>","<p>We investigate the thermodynamic stability of carbon-rich icosahedral boron carbide at different compositions, ranging from B4C to B2C, using first-principles calculations. Apart fromB4C, generally addressed in the literature, B2.5C, represented by B10C2p (C-C), where C-p and (C-C) denote a carbon atom occupying the polar site of the icosahedral cluster and a diatomic carbon chain, respectively, is predicted to be thermodynamically stable under high pressures with respect to B4C as well as pure boron and carbon phases. The thermodynamic stability of B2.5C is determined by the Gibbs free energy G as a function of pressure p and temperature T, in which the contributions from the lattice vibrations and the configurational disorder are obtained within the quasiharmonic and the mean-field approximations, respectively. The stability range of B2.5C is then illustrated through the p-T phase diagrams. Depending on the temperatures, the stability range of B2.5C is predicted to be within the range between 40 and 67 GPa. At T greater than or similar to 500 K, the icosahedral C-p atoms in B2.5C configurationally disorder at the polar sites. By investigating the properties of B2.5C, e.g., elastic constants and phonon and electronic density of states, we demonstrate that B2.5C is both mechanically and dynamically stable at zero pressure, and is an electrical semiconductor. Furthermore, based on the sketched phase diagrams, a possible route for experimental synthesis of B2.5C as well as a fingerprint for its characterization from the simulations of x-ray powder diffraction pattern are suggested.</p>","","","","","","","","","","","","","2016-09-23","2016-09-26","2018-08-29","","","3","","0","urn:nbn:se:liu:diva-136813","","","","054104","false","","","" "940230","Potapkin, V. (Forschungszentrum Julich, Germany);Dubrovinsky, L. (University of Bayreuth, Germany);Sergueev, I. (DESY, Germany);Ekholm, Marcus [marek10] [0000-0002-7563-1494] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Kantor, I. (European Synchrotron Radiat Facil, France);Bessas, D. (European Synchrotron Radiat Facil, France);Bykova, E. (University of Bayreuth, Germany);Prakapenka, V. (University of Chicago, IL 60437 USA);Hermann, R. P. (Forschungszentrum Julich, Germany; Oak Ridge National Lab, TN 37831 USA);Rueffer, R. (European Synchrotron Radiat Facil, France);Cerantola, V. (University of Bayreuth, Germany);Jönsson, Johan [johjo06] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Olovsson, W. [n/a] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Mankovsky, S. (University of Munich, Germany);Ebert, H. (University of Munich, Germany);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (National University of Science and Technology MISIS, Russia; Tomsk State University, Russia)","Magnetic interactions in NiO at ultrahigh pressure","Artikel i tidskrift","Refereegranskat","eng","PHYSICAL REVIEW B","2469-9950","","published","93","20","","201110","","2016","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.93.201110","000376638400001","","","urn:nbn:se:liu:diva-129492","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|National Science Foundation-Earth Sciences [EAR-1128799]; Department of Energy-GeoSciences [DE-FG02-94ER14466]; DOE Office of Science [DE-AC02-06CH11357]; Helmholtz Association; Materials Sciences and Engineering Division, Office of Basic Energy Sciences, U.S. Department of Energy; Swedish Government Strategic Research Area Grants Swedish e-Science Research Center (SeRC) and in Materials Science on Functional Materials at Linkoping University [2009 00971]; Knut and Alice Wallenbergs Foundation project Strong Field Physics and New States of Matter; Swedish Foundation for Strategic Research program SRL Grant [10-0026]; Swedish Research Council (VR) [2015-04391]; Grant of Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Tomsk State University Academic D.I. Mendeleev Fund Program</p>","<p>Magnetic properties of NiO have been studied in the multimegabar pressure range by nuclear forward scattering of synchrotron radiation using the 67.4 keV Mossbauer transition of Ni-61. The observed magnetic hyperfine splitting confirms the antiferromagnetic state of NiO up to 280 GPa, the highest pressure where magnetism has been observed so far, in any material. Remarkably, the hyperfine field increases from 8.47 T at ambient pressure to similar to 24 T at the highest pressure, ruling out the possibility of a magnetic collapse. A joint x-ray diffraction and extended x-ray-absorption fine structure investigation reveals that NiO remains in a distorted sodium chloride structure in the entire studied pressure range. Ab initio calculations support the experimental observations, and further indicate a complete absence of Mott transition in NiO up to at least 280 GPa.</p>","","","","","","","","","","","","","2016-06-20","2016-06-20","2018-08-29","","","16","","0","","","","","","false","","","" "780816","Puglisi, Donatella [donpu97] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Eriksson, Jens [jener58] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tillämpad sensorvetenskap [11901]) (Linköpings universitet [276], Tekniska högskolan [1751]);Bur, Christian [chrbu93] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tillämpad sensorvetenskap [11901]) (Linköpings universitet [276], Tekniska högskolan [1751]) (Saarland University, Lab for Measurement Technology, Germany);Schuetze, Andreas (Saarland University, Germany) (Lab for Measurement Technology);Lloyd Spetz, Anita [anill63] [0000-0002-2817-3574] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tillämpad sensorvetenskap [11901]) (Linköpings universitet [276], Tekniska högskolan [1751]);Andersson, Mike [mikan22] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tillämpad sensorvetenskap [11901]) (Linköpings universitet [276], Tekniska högskolan [1751])","Catalytic metal-gate field effect transistors based on SiC for indoor air quality control","Artikel i tidskrift","Refereegranskat","eng","Journal of Sensors and Sensor Systems","2194-8771","published","4","","","1","8","2015","","","Germany","Copernicus","","","","","","10.5194/jsss-4-1-2015","","","","urn:nbn:se:liu:diva-113295","","","silicon carbide;field effect transistor;volatile organic compounds;air quality control","Övrig annan teknik (21199)","","SENSIndoor (grant agreement no. 604311)","","<p>High-temperature iridium-gated field effect transistors based on silicon carbide have been used for sensitive detection of specific volatile organic compounds (VOCs) in concentrations of health concern, for indoorair quality monitoring and control. Formaldehyde, naphthalene, and benzene were studied as hazardous VOCs at parts per billion (ppb) down to sub-ppb levels. The sensor performance and characteristics were investigated at a constant temperature of 330° C and at different levels of relative humidity up to 60 %, showing good stability and repeatability of the sensor response, and excellent detection limits in the sub-ppb range.</p>","","","","","","","","","","","","","2015-01-15","2015-01-15","2015-01-21","http://liu.diva-portal.org/smash/get/diva2:780816/FULLTEXT01.pdf","EU, FP7, Sjunde ramprogrammet [604311]","6","","0","","","E-MRS Spring Meeting 2014 Symposium B: Advanced Functional Materials for Environmental Monitoring and ApplicationsLille Congress Center, Lille (France), 26-29 May 2014","","","true","true","","" "843917","Faber, Felix (University of Basel, Switzerland; University of Basel, Switzerland; University of Basel, Switzerland);Lindmaa, Alexander [aleli16] [0000-0001-5439-711X] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);von Lilienfeld, O. Anatole (University of Basel, Switzerland; Argonne Leadership Comp Facil, IL 60439 USA; Argonne National Lab, IL 60439 USA);Armiento, Rickard [ricar47] [0000-0002-5571-0814] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Crystal structure representations for machine learning models of formation energies","Artikel i tidskrift","Refereegranskat","eng","International Journal of Quantum Chemistry","0020-7608","1097-461X","published","115","16","","1094","1101","2015","","","","Wiley","","","","","","","10.1002/qua.24917","000357606000010","","","urn:nbn:se:liu:diva-120326","","","machine learning; formation energies; representations; crystal structure; periodic systems","Fysik (103)","","","<p>Funding Agencies|Swedish Research Council (VR) [621-2011-4249]; Linnaeus Environment at Linkoping on Nanoscale Functional Materials - VR; Swiss National Science foundation [PP00P2_138932]; Office of Science of the U.S. DOE [DE-AC02-06CH11357]; Air Force Office of Scientific Research, Air Force Material Command, USAF [FA9550-15-1-0026]</p>","<p>We introduce and evaluate a set of feature vector representations of crystal structures for machine learning (ML) models of formation energies of solids. ML models of atomization energies of organic molecules have been successful using a Coulomb matrix representation of the molecule. We consider three ways to generalize such representations to periodic systems: (i) a matrix where each element is related to the Ewald sum of the electrostatic interaction between two different atoms in the unit cell repeated over the lattice; (ii) an extended Coulomb-like matrix that takes into account a number of neighboring unit cells; and (iii) an ansatz that mimics the periodicity and the basic features of the elements in the Ewald sum matrix using a sine function of the crystal coordinates of the atoms. The representations are compared for a Laplacian kernel with Manhattan norm, trained to reproduce formation energies using a dataset of 3938 crystal structures obtained from the Materials Project. For training sets consisting of 3000 crystals, the generalization error in predicting formation energies of new structures corresponds to (i) 0.49, (ii) 0.64, and (iii) 0.37eV/atom for the respective representations.</p>","","","","","","","","","","","","","2015-07-31","2015-07-31","2017-11-01","","","4","","1","urn:nbn:se:liu:diva-139767","","","","","false","","","" "893554","Thomson, Mark D. (Physikalisches Institut, Goethe-University, D-60438 Frankfurt am Main,Germany);Meng, Fanqi (Physikalisches Institut, Goethe-University, D-60438 Frankfurt am am Main, Germany);Sernelius, Bo E. [bose02] [0000-0002-6281-868X] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Roskos, Hartmut G. (Physikalisches Institut, Goethe-University, D-60438 Frankfurt am Main)","Relativistic Doppler reflection as a probe for the initialrelaxation of a non-equilibrium electron-hole plasma in silicon","Artikel i tidskrift","Refereegranskat","eng","Journal of Physics, Conference Series","1742-6588","1742-6596","published","647","","","012016","012019","2015","","","","Institute of Physics (IOP)","","","","","","","10.1088/1742-6596/647/1/012016","000366236800016","","","urn:nbn:se:liu:diva-123876","","","Relativistic Doppler reflection;non-equilibrium electron-hole plasma;relaxation;silicon.","Den kondenserade materiens fysik (10304)","","","","<p>This paper reviews the status of investigations of the relativistic Doppler reflectionof a broadband terahertz pulse at a counter-propagating plasma front of photo-excited chargecarriers in undoped silicon. When a THz pulse with 20-THz bandwidth impinges onto amoving plasma front with a carrier density in the range of 10¹⁹ per cm³, one observes a spectralup-shift, which is, however, much less pronounced than expected from simulations assuming a Drude plasma characterized by a single carrier relaxation time τ of the order of 15-100 fs.Qualitative agreement between simulations and experiments can be achieved if τ is chosen tobe less than 5 fs. In order to explore carrier relaxation in more detail, optical-pump/THz-probeexperiments in the conventional co-propagation geometry were performed. If the pump-probedelay is long enough for monitoring of the equilibrium value of the scattering time, τ rangesfrom 200 fs at low carrier density to 20 fs in the 10¹⁹-cm^-3 density range. For small (subpicosecond)pump-probe delay, the data reveal a significantly faster scattering, which slowsdown during energy relaxation of the charge carriers.</p>","","","","","","","","","","","","","2016-01-12","2016-01-12","2017-11-30","http://liu.diva-portal.org/smash/get/diva2:893554/FULLTEXT02.pdf","Deutsche Forschungsgemeinschaft (DFG)","4","","1","","","19th International Conference on Electron Dynamics in Semiconductors, Optoelectronics and Nanostructures (EDISON'19), Salamanca, Spain, 29 June to 2 July 2015","","","true","true","","" "892924","Tholander, Christopher [chrth86] [0000-0001-6914-9354] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Tasnadi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Hultman, Lars [larhu75] [0000-0002-2837-3656] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Birch, Jens [jenbi91] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Max Planck Institute Eisenforsch GmbH, Germany)","Large piezoelectric response of quarternary wurtzite nitride alloys and its physical origin from first principles","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","1550-235X","published","92","17","","174119","","2015","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.92.174119","000365506400001","","","urn:nbn:se:liu:diva-123799","","","","Fysik (103)","","","<p>Funding Agencies|Knut and Alice Wallenberg Foundation Scholar Grant; Swedish Research Council (VR) Linkoping Linnaeus Initiative LiLi-NFM [2008-6572]; Swedish Government Strategic Research Area Grant in Materials Science on Advanced Functional Materials [MatLiU 2009-00971]; Swedish Research Council [621-2011-4417, 330-2014-6336]; Swedish Foundation for Strategic Research (SSF) Programme SRL [10-0026]; Swedish Research Council (VR) [621-2011-4426]</p>","<p>The potential of quarternary wurtzite TMx/2Mx/2Al1-xN (TM = Ti, Zr, Hf; M = Mg, Ca, Zn) alloys for piezoelectric applications is investigated using first-principles calculations. All considered alloys show increased piezoelectric response compared to pure AlN, and competing with the best ternary system proven to date: ScAlN. (Zr, Hf)(x/2)(Mg, Ca)(x/2)Al1-xN alloys are particularly promising. Calculations reveal positive mixing enthalpies indicative for phase separating systems; their values are smaller compared to related nitride alloys, which still can be grown as metastable thin films. The wurtzite phase of the alloys is lowest in energy at least up to x = 0.5 and for Tix/2Znx/2Al1-xN in the full composition range. Moreover, calculations reveal that wurtzite TM0.5Zn0.5N (TM = Ti, Zr, Hf) are piezoelectric alloys with d(33,f) = 19.95, 29.89, and 24.65 pC/N respectively, up to six times that of AlN. Finally, we discuss the physical origin behind the increased piezoelectric response and show that the energy difference between tetrahedrally coordinated zinc-blende (B3) and the layered hexagonal (B-k) phases of the TM0.5M0.5N alloy can be used as a descriptor in a high-throughput search for complex wurtzite alloys with high piezoelectric response.</p>","","","","","","","","","","","","","2016-01-11","2016-01-11","2017-11-30","http://liu.diva-portal.org/smash/get/diva2:892924/FULLTEXT01.pdf","","6","","2","urn:nbn:se:liu:diva-125919","","","","","false","","","" "892928","Belicev, P. P. (University of Belgrade, Serbia);Gligoric, G. (University of Belgrade, Serbia);Radosavljevic, A. (University of Belgrade, Serbia);Maluckov, A. (University of Belgrade, Serbia);Stepic, M. (University of Belgrade, Serbia);Vicencio, R. A. (University of Chile, Chile; University of Chile, Chile);Johansson, Magnus [magjo23] [0000-0001-6708-1560] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Localized modes in nonlinear binary kagome ribbons","Artikel i tidskrift","Refereegranskat","eng","Physical Review E. Statistical, Nonlinear, and Soft Matter Physics","1539-3755","1550-2376","published","92","5","","052916","","2015","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevE.92.052916","000365871500028","26651771","","urn:nbn:se:liu:diva-123797","","","","Fysik (103)","","","<p>Funding Agencies|Swedish Research Council within the Swedish Research Links programme [348-2013-6752]; Sweden-Chilean-Serbian trilateral project ""Control of light and matter waves propagation and localization in photonic lattices""; Ministry of Education, Science and Technological Development of Republic of Serbia [III45010]; Fondecyt Grant [1151444]; Programa ICM [RC-130001]; Programa de Financiamiento Basal [FB0824]</p>","<p>The localized mode propagation in binary nonlinear kagome ribbons is investigated with the premise to ensure controlled light propagation through photonic lattice media. Particularity of the linear system characterized by the dispersionless flat band in the spectrum is the opening of new minigaps due to the ""binarism."" Together with the presence of nonlinearity, this determines the guiding mode types and properties. Nonlinearity destabilizes the staggered rings found to be nondiffracting in the linear system, but can give rise to dynamically stable ringlike solutions of several types: unstaggered rings, low-power staggered rings, hour-glass-like solutions, and vortex rings with high power. The type of solutions, i.e., the energy and angular momentum circulation through the nonlinear lattice, can be controlled by suitable initial excitation of the ribbon. In addition, by controlling the system ""binarism"" various localized modes can be generated and guided through the system, owing to the opening of the minigaps in the spectrum. All these findings offer diverse technical possibilities, especially with respect to the high-speed optical communications and high-power lasers.</p>","","","","","","","","","","","","","2016-01-11","2016-01-11","2017-11-30","http://liu.diva-portal.org/smash/get/diva2:892928/FULLTEXT01.pdf","","7","","0","","","","","","false","","","" "892921","Wang, Weimin [weiwa49] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Yt- och Halvledarfysik [2233]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Olovsson, Weine [weiol14] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Uhrberg, Roger [roguh04] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Yt- och Halvledarfysik [2233]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Experimental and theoretical determination of sigma bands on (""2 root 3 x 2 root 3"") silicene grown on Ag(111)","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","1550-235X","published","92","20","","205427","","2015","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.92.205427","000365509100011","","","urn:nbn:se:liu:diva-123801","","","","Fysik (103)","","","<p>Funding Agencies|Swedish Research Council [621-2010-3746, 621-2014-4764, 621-2011-4426, 2008-6582]; Linkoping Linnaeus Initiative for Novel Functional Materials; Swedish National Infrastructure for Computing (SNIC)</p>","<p>Silicene, the two-dimensional (2D) allotrope of silicon, has very recently attracted a lot of attention. It has a structure that is similar to graphene and it is theoretically predicted to show the same kind of electronic properties which have put graphene into the focus of large research and development projects worldwide. In particular, a 2D structure made from Si is of high interest because of the application potential in Si-based electronic devices. However, so far there is not much known about the silicene band structure from experimental studies. A comprehensive study is here presented of the atomic and electronic structure of the silicene phase on Ag(111) denoted as (2 root 3 x 2 root 3)R30 degrees in the literature. Low energy electron diffraction (LEED) shows an unconventional rotated (""2 root 3 x 2 root 3"") pattern with a complicated set of split diffraction spots. Scanning tunneling microscopy (STM) results reveal a Ag(111) surface that is homogeneously covered by the (""2 root 3 x 2 root 3"") silicene which exhibits an additional quasiperiodic long-range ordered superstructure. The complex structure, revealed by STM, has been investigated in detail and we present a consistent picture of the silicene structure based on both STM and LEED. The homogeneous coverage by the (""2 root 3 x 2 root 3"") silicene facilitated an angle-resolved photoelectron spectroscopy study which reveals a silicene band structure of unprecedented detail. Here we report four silicene bands which are compared to calculated dispersions based on a relaxed (2 root 3 x 2 root 3) model. We find good qualitative agreement between the experimentally observed bands and calculated silicene bands of sigma character.</p>","","","","","","","","","","","","","2016-01-11","2016-01-11","2017-11-30","http://liu.diva-portal.org/smash/get/diva2:892921/FULLTEXT01.pdf","","3","","2","","","","","","false","","","" "886250","Johansson, Magnus [magjo23] [0000-0001-6708-1560] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Editorial Material: Comment on ""Localization-delocalization transition in self-dual quasi-periodic lattices"" by Sun M. L. et al. in EPL, vol 112, issue 1, pp","Artikel i tidskrift","Övrigt vetenskapligt","eng","Europhysics letters","0295-5075","1286-4854","published","112","1","","17002","","2015","","","","EPL ASSOCIATION, EUROPEAN PHYSICAL SOCIETY","","","","","","","10.1209/0295-5075/112/17002","000365131500019","","","urn:nbn:se:liu:diva-123531","","","","Fysik (103)","","","","<p>n/a</p>","","","","","","","","","","","","","2015-12-21","2015-12-22","2017-12-01","","","1","","1","","editorialMaterial","","","","false","","","" "877390","Brodin, G. (Umeå University, Sweden);Stenflo, Lennart [lenst65] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Three-wave coupling coefficients for perpendicular wave propagation in a magnetized plasma","Artikel i tidskrift","Refereegranskat","eng","Physics of Plasmas","1070-664X","1089-7674","published","22","10","","","","2015","","","","AMER INST PHYSICS","","","","","","","10.1063/1.4934938","000364403600128","","","urn:nbn:se:liu:diva-123160","","","","Fysik (103)","","","","<p>The resonant interaction between three waves in a uniform magnetized plasma is reconsidered. Starting from previous kinetic expressions, we limit our investigation to waves propagating perpendicularly to the external magnetic field. It is shown that reliable results can only be obtained in the two-dimensional case, i.e., when the wave vectors have both x and y components. (C) 2015 AIP Publishing LLC.</p>","","","","","","","","","","","","","2015-12-04","2015-12-07","2017-12-01","http://liu.diva-portal.org/smash/get/diva2:877390/FULLTEXT01.pdf","","2","","1","","","","","104503","false","","","" "864315","Lukinov, T. (Royal Institute Technology KTH, Sweden);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Belonoshko, A. B. (Royal Institute Technology KTH, Sweden)","Sound velocity in shock compressed molybdenum obtained by ab initio molecular dynamics","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","1550-235X","published","92","6","","060101","","2015","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.92.060101","000362212200001","","","urn:nbn:se:liu:diva-122219","","","","Fysik (103)","","","<p>Funding Agencies|Swedish Research Council (VR) [2013-5767, 2014-4750]</p>","<p>The sound velocity of Mo along the Hugoniot adiabat is calculated from first principles using density-functional theory based molecular dynamics. These data are compared to the sound velocity as measured in recent experiments. The theoretical and experimental Hugoniot and sound velocities are in very good agreement up to pressures of 210 GPa and temperatures of 3700 K on the Hugoniot. However, above that point the experiment and theory diverge. This implies that Mo undergoes a phase transition at about the same point. Considering that the melting point of Mo is likely much higher at that pressure, the related change in the sound velocity in experiment can be ascribed to a solid-solid transition.</p>","","","","","","","","","","","","","2015-10-23","2015-10-26","2017-12-01","http://liu.diva-portal.org/smash/get/diva2:864315/FULLTEXT01.pdf","","3","","2","","","","","","false","","","" "875198","Shulumba, Nina [ninsh46] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Saarland, Germany);Hellman, Olle [olohe96] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Division of Engineering and Applied Science, California Institute of Technology, Pasadena, California, USA);Rogström, Lina [linro82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Raza, Zamaan [zamra51] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Tasnádi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Materials Modeling and Development Laboratory, NUST “MISIS”, Moscow, Russia / LACOMAS Laboratory, Tomsk State University, Tomsk, Russia);Odén, Magnus [magod41] [0000-0002-2286-5588] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Temperature-dependent elastic properties of Ti1_−xAl_xN alloys","Artikel i tidskrift","Refereegranskat","eng","Applied Physics Letters","0003-6951","1077-3118","published","107","23","","","","2015","","","","","","","","","","","10.1063/1.4936896","000367010800017","","","urn:nbn:se:liu:diva-122957","","","","Den kondenserade materiens fysik (10304);Fysik (103)","","","<p>Funding agencies: Swedish Research Council (VR) [621-2011-4426, 621-2012-4401, 637-2013-7296]; Swedish Foundation for Strategic Research (SSF) [RMA08-0069, SRL10-0026]; VINNOVA [2013-02355(MC2)]; Erasmus Mundus Joint European Doctoral Program DocMASE; Ministry of Education</p><p>Vid tidpunkten för disputation förelåg publikation som manuskript</p>","<p>Ti1_−xAl_xN is a technologically important alloy that undergoes a process of high temperature age-hardening that is strongly influenced by its elastic properties. We have performed first principles calculations of the elastic constants and anisotropy using the newly developed symmetry imposed force constant temperature dependent effective potential method, that include lattice vibrations and therefore the effects of temperature, including thermal expansion and intrinsic anharmonicity. These are compared with in situ high temperature x-ray diffraction measurements of the lattice parameter. We show that anharmonic effects are crucial to the recovery of finite temperature elasticity. The effects of thermal expansion and intrinsic anharmonicity on the elastic constants are of the same order, and cannot be considered separately. Furthermore, the effect of thermal expansion on elastic constants is such that the volume change induced by zero point motion has a significant effect. For TiAlN, the elastic constants soften non-uniformly with temperature: <em>C</em>₁₁ decreases substantially when the temperature increases for all compositions, resulting in an increased anisotropy. These findings suggest that an increased Al content and annealing at higher temperatures will result in a harder alloy.</p>","","","","","","","","","","","","","2015-11-30","2015-11-30","2017-12-01","http://liu.diva-portal.org/smash/get/diva2:875198/FULLTEXT01.pdf","","7","","2","urn:nbn:se:liu:diva-122949","","","","","true","","","" "860769","Ivády, Viktor [vikiv58] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Hungarian Academic Science, Hungary);Szasz, Krisztian (Hungarian Academic Science, Hungary);Falk, Abram L. (University of Chicago, IL 60637 USA; IBM Corp, NY 10598 USA);Klimov, Paul V. (University of Chicago, IL 60637 USA; University of Calif Santa Barbara, CA 93106 USA);Christle, David J. (University of Chicago, IL 60637 USA; University of Calif Santa Barbara, CA 93106 USA);Janzén, Erik [erija14] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (National University of Science and Technology MISIS, Russia; Tomsk State University, Russia);Awschalom, David D. (University of Chicago, IL 60637 USA);Gali, Adam (Hungarian Academic Science, Hungary; Budapest University of Technology and Econ, Hungary)","Theoretical model of dynamic spin polarization of nuclei coupled to paramagnetic point defects in diamond and silicon carbide","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","1550-235X","published","92","11","","115206","","2015","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevB.92.115206","000361370600003","","","urn:nbn:se:liu:diva-121891","","","","Fysik (103);Kemi (104)","","","<p>Funding Agencies|Knut and Alice Wallenberg Foundation ""Isotopic Control for Ultimate Materials Properties""; Swedish Research Council (VR) [621-2011-4426, 621-2011-4249]; Swedish Foundation for Strategic Research program SRL [10-0026]; Grant of Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Tomsk State University Academic D. I. Mendeleev Fund Program [8.1.18.2015]; Swedish National Infrastructure for Computing Grants [SNIC 2013/1-331]; ""Lendulet program"" of Hungarian Academy of Sciences</p>","<p>Dynamic nuclear spin polarization (DNP) mediated by paramagnetic point defects in semiconductors is a key resource for both initializing nuclear quantum memories and producing nuclear hyperpolarization. DNP is therefore an important process in the field of quantum-information processing, sensitivity-enhanced nuclear magnetic resonance, and nuclear-spin-based spintronics. DNP based on optical pumping of point defects has been demonstrated by using the electron spin of nitrogen-vacancy (NV) center in diamond, and more recently, by using divacancy and related defect spins in hexagonal silicon carbide (SiC). Here, we describe a general model for these optical DNP processes that allows the effects of many microscopic processes to be integrated. Applying this theory, we gain a deeper insight into dynamic nuclear spin polarization and the physics of diamond and SiC defects. Our results are in good agreement with experimental observations and provide a detailed and unified understanding. In particular, our findings show that the defect electron spin coherence times and excited state lifetimes are crucial factors in the entire DNP process.</p>","","","","","","","","","","","","","2015-10-12","2015-10-13","2017-12-01","http://liu.diva-portal.org/smash/get/diva2:860769/FULLTEXT01.pdf","","9","","2","urn:nbn:se:liu:diva-131853","","","","","false","","","" "860767","Johansson, Magnus [magjo23] [0000-0001-6708-1560] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Naether, Uta (University of Zaragoza, Spain; University of Zaragoza, Spain);Vicencio, Rodrigo A. (University of Chile, Chile; University of Chile, Chile)","Compactification tuning for nonlinear localized modes in sawtooth lattices","Artikel i tidskrift","Refereegranskat","eng","Physical Review E. Statistical, Nonlinear, and Soft Matter Physics","1539-3755","1550-2376","published","92","3-1","","032912","","2015","","","","AMER PHYSICAL SOC","","","","","","","10.1103/PhysRevE.92.032912","000361310700008","26465545","","urn:nbn:se:liu:diva-121892","","","","Annan fysik (10399)","","","<p>Funding Agencies|Swedish Research Council within the Swedish Research Links program [348-2013-6752]; Spanish government [FIS 2011-25167, FPDI-2013-18422]; Aragon project (Grupo FENOL); Programa ICM grant [RC130001]; Programa de Financiamiento Basal de CONICYT [FB0824/2008]; FONDECYT [1151444]</p>","<p>We discuss the properties of nonlinear localized modes in sawtooth lattices, in the framework of a discrete nonlinear Schrodinger modelwith general on-site nonlinearity. Analytic conditions for existence of exact compact three-site solutions are obtained, and explicitly illustrated for the cases of power-law (cubic) and saturable nonlinearities. These nonlinear compact modes appear as continuations of linear compact modes belonging to a flat dispersion band. While for the linear system a compact mode exists only for one specific ratio of the two different coupling constants, nonlinearity may lead to compactification of otherwise noncompact localized modes for a range of coupling ratios, at some specific power. For saturable lattices, the compactification power can be tuned by also varying the nonlinear parameter. Introducing different on-site energies and anisotropic couplings yields further possibilities for compactness tuning. The properties of strongly localized modes are investigated numerically for cubic and saturable nonlinearities, and in particular their stability over large parameter regimes is shown. Since the linear flat band is isolated, its compact modes may be continued into compact nonlinear modes both for focusing and defocusing nonlinearities. Results are discussed in relation to recent realizations of sawtooth photonic lattices.</p>","","","","","","","","","","","","","2015-10-12","2015-10-13","2017-12-01","http://liu.diva-portal.org/smash/get/diva2:860767/FULLTEXT01.pdf","","3","","0","","","","","","false","","","" "859370","Dubrovinsky, L. (University of Bayreuth, Germany);Dubrovinskaia, N. (University of Bayreuth, Germany);Bykova, E. (University of Bayreuth, Germany; University of Bayreuth, Germany);Bykov, M. (University of Bayreuth, Germany);Prakapenka, V. (University of Chicago, IL 60437 USA);Prescher, C. (University of Chicago, IL 60437 USA);Glazyrin, K. (Deutsch Elektronen Synchrotron DESY, Germany);Liermann, H. -P. (Deutsch Elektronen Synchrotron DESY, Germany);Hanfland, M. (European Synchrotron Radiat Facil, France);Ekholm, Marcus [marek10] [0000-0002-7563-1494] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Feng, Qingguo [qinfe69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Pourovskii, L. V. (Linköpings universitet [276], Tekniska fakulteten [872902]) (Ecole Polytech, France) (Swedish E Sci Res Ctr SeRC);Katsnelson, M. I. (Radboud University of Nijmegen, Netherlands; Ural Federal University, Russia);Wills, J. M. (Los Alamos National Lab, NM 87545 USA);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (National University of Science and Technology MISIS, Russia)","The most incompressible metal osmium at static pressures above 750 gigapascals","Artikel i tidskrift","Refereegranskat","eng","Nature","0028-0836","1476-4687","published","525","7568","","226","+","2015","","","","NATURE PUBLISHING GROUP","","","","","","","10.1038/nature14681","000360927400033","26302297","","urn:nbn:se:liu:diva-121742","","","","Fysik (103)","","","<p>Funding Agencies|Deutsche Forschungsgemeinschaft (DFG); Federal Ministry of Education and Research (BMBF), Germany; DFG through Heisenberg Program; DFG [DU 954-8/1]; BMBF [5K13WC3, O5K2013]; Swedish Foundation for Strategic Research programme SRL [10-0026]; Swedish Research Council (VR) [621-2011-4426]; Swedish Government Strategic Research Area Grant Swedish e-Science Research Centre (SeRC); Materials Science ""Advanced Functional Materials"" (AFM); Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; ERC [338957]; NWO; National Science Foundation - Earth Sciences [EAR-1128799]; Department of Energy - GeoSciences [DE-FG02-94ER14466]; DOE Office of Science by Argonne National Laboratory [DE-AC02-06CH11357]</p>","<p>Metallic osmium (Os) is one of the most exceptional elemental materials, having, at ambient pressure, the highest known density and one of the highest cohesive energies and melting temperatures(1). It is also very incompressible(2-4), but its high-pressure behaviour is not well understood because it has been studied(2-6) so far only at pressures below 75 gigapascals. Here we report powder X-ray diffraction measurements on Os at multi-megabar pressures using both conventional and double-stage diamond anvil cells(7), with accurate pressure determination ensured by first obtaining self-consistent equations of state of gold, platinum, and tungsten in static experiments up to 500 gigapascals. These measurements allow us to show that Os retains its hexagonal close-packed structure upon compression to over 770 gigapascals. But although its molar volume monotonically decreases with pressure, the unit cell parameter ratio of Os exhibits anomalies at approximately 150 gigapascals and 440 gigapascals. Dynamical mean-field theory calculations suggest that the former anomaly is a signature of the topological change of the Fermi surface for valence electrons. However, the anomaly at 440 gigapascals might be related to an electronic transition associated with pressure-induced interactions between core electrons. The ability to affect the core electrons under static high-pressure experimental conditions, even for incompressible metals such as Os, opens up opportunities to search for new states of matter under extreme compression.</p>","","","","","","","","","","","","","2015-10-05","2015-10-06","2017-12-01","","","15","","2","","","","","","false","","","" "859362","Brodin, G. (Umeå University, Sweden);Stenflo, Lennart [lenst65] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Nonlinear wave interactions of kinetic sound waves","Artikel i tidskrift","Refereegranskat","eng","Annales Geophysicae","0992-7689","1432-0576","published","33","8","","1007","1010","2015","","","","COPERNICUS GESELLSCHAFT MBH","","","","","","","10.5194/angeo-33-1007-2015","000360651100007","","","urn:nbn:se:liu:diva-121769","","","Magnetospheric physics (solar wind-magnetosphere interactions)","Fysik (103)","","","","<p>We reconsider the nonlinear resonant interaction between three electrostatic waves in a magnetized plasma. The general coupling coefficients derived from kinetic theory are reduced here to the low-frequency limit. The main contribution to the coupling coefficient we find in this way agrees with the coefficient recently presented in Annales Geophysicae. But we also deduce another contribution which sometimes can be important, and which qualitatively agrees with that of an even more recent paper. We have thus demonstrated how results derived from fluid theory can be improved and generalized by means of kinetic theory. Possible extensions of our results are outlined.</p>","","","","","","","","","","","","","2015-10-05","2015-10-06","2017-12-01","http://liu.diva-portal.org/smash/get/diva2:859362/FULLTEXT01.pdf","","2","","1","","","","","","false","","","" "843900","Eleonora Bove, Livia (University of Paris 06, France; Ecole Polytech Federal Lausanne, Switzerland);Gaal, Richard (Ecole Polytech Federal Lausanne, Switzerland);Raza, Zamaan [zamra51] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (University of Paris 06, France);Ludl, Adriaan-Alexander (University of Paris 06, France);Klotz, Stefan (University of Paris 06, France);Marco Saitta, Antonino (University of Paris 06, France);Goncharov, Alexander F. (Carnegie Institute Science, DC 20015 USA);Gillet, Philippe (Ecole Polytech Federal Lausanne, Switzerland)","Effect of salt on the H-bond symmetrization in ice","Artikel i tidskrift","Refereegranskat","eng","Proceedings of the National Academy of Sciences of the United States of America","0027-8424","1091-6490","published","112","27","","8216","8220","2015","","","","National Academy of Sciences","","","","","","","10.1073/pnas.1502438112","000357527600040","26100876","","urn:nbn:se:liu:diva-120342","","","salty ices; extreme conditions; ice bodies; H-bond symmetrization; proton quantum effects","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swiss National Science Foundation through FNS Grant [200021-149847]; French state funds [ANR-13-IS04-0006-01]; Investissements dAvenir programme [ANR-11-IDEX-0004-02]; Grand Equipement National de Calcul Intensif French National Supercomputing Facility [x2013091387]</p>","<p>The richness of the phase diagram of water reduces drastically at very high pressures where only two molecular phases, proton-disordered ice VII and proton-ordered ice VIII, are known. Both phases transform to the centered hydrogen bond atomic phase ice X above about 60 GPa, i.e., at pressures experienced in the interior of large ice bodies in the universe, such as Saturn and Neptune, where nonmolecular ice is thought to be the most abundant phase of water. In this work, we investigate, by Raman spectroscopy up to megabar pressures and ab initio simulations, how the transformation of ice VII in ice X is affected by the presence of salt inclusions in the ice lattice. Considerable amounts of salt can be included in ice VII structure under pressure via rock-ice interaction at depth and processes occurring during planetary accretion. Our study reveals that the presence of salt hinders proton order and hydrogen bond symmetrization, and pushes ice VII to ice X transformation to higher and higher pressures as the concentration of salt is increased.</p>","","","","","","","","","","","","","2015-07-31","2015-07-31","2017-12-04","","","8","","2","","","","","","false","","","" "827274","Ferreira da Silva, Antonio (University of Federal Bahia, Brazil);Levine, Alexandre (University of Sao Paulo, Brazil);Sadre Momtaz, Zahra (University of Sao Paulo, Brazil);Boudinov, Henri (University of Federal Rio Grande do Sul, Brazil);Sernelius, Bo [bose02] [0000-0002-6281-868X] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Magnetoresistance of doped silicon","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","1550-235X","published","91","21","","214414","","2015","","","","American Physical Society","","","","","","","10.1103/PhysRevB.91.214414","000355825000002","","","urn:nbn:se:liu:diva-119788","","","","Fysik (103)","","","<p>Funding Agencies|National Research Council of Scientific and Technological Development (CNPq); Bahia Research Foundation (FAPESB)/PRONEX; Sao Paulo Research Foundation (FAPESP)</p>","<p>We have performed longitudinal magnetoresistance measurements on heavily n-doped silicon for donor concentrations exceeding the critical value for the metal-nonmetal transition. The results are compared to those from a many-body theory where the donor electrons are assumed to reside at the bottom of the many-valley conduction band of the host. Good qualitative agreement between theory and experiment is obtained.</p>","","","","","","","","","","","","","2015-06-26","2015-06-26","2017-12-04","http://liu.diva-portal.org/smash/get/diva2:827274/FULLTEXT01.pdf","","5","","2","","","","","","false","","","" "827271","Vekilova, Olga [olgve20] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]) (Royal Institute Technology KTH, Sweden);Pourovskii, L. V. (Swedish E Sci Res Ctr, Linkoping, Sweden; Ecole Polytech, France);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (National University of Science and Technology MISiS, Russia);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Electronic correlations in Fe at Earths inner core conditions: Effects of alloying with Ni","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","1550-235X","published","91","24","","245116","","2015","","","","American Physical Society","","","","","","","10.1103/PhysRevB.91.245116","000355721300007","","","urn:nbn:se:liu:diva-119789","","","","Fysik (103)","","","<p>Funding Agencies|HPC-Europa2; Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of NUST ""MISiS"" [K3-2015-038]; PHD DALEN [26228RM]; Swedish Research Council (VR) [621-2011-4426, 2011-42-59, 2014-4750]; Linkoping Linnaeus Initiative for Novel Functional Materials (LiLi-NFM); Swedish Foundation for Strategic Research (SSF) program [SRL10-0026]; Swedish Government Strategic Research Area Grant in Materials Science ""Advanced Functional Materials"" (AFM); Swedish e-Science Research Centre (SeRC); Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]</p>","<p>We have studied the body-centered cubic (bcc), face-centered cubic (fcc), and hexagonal close-packed (hcp) phases of Fe alloyed with 25 at.% of Ni at Earths core conditions using an ab initio local density approximation + dynamical mean-field theory approach. The alloys have been modeled by ordered crystal structures based on the bcc, fcc, and hcp unit cells with the minimum possible cell size allowing for the proper composition. Our calculations demonstrate that the strength of electronic correlations on the Fe 3d shell is highly sensitive to the phase and local environment. In the bcc phase, the 3d electrons at the Fe site with Fe only nearest neighbors remain rather strongly correlated, even at extreme pressure-temperature conditions, with the local and uniform magnetic susceptibility exhibiting a Curie-Weiss-like temperature evolution and the quasiparticle lifetime Gamma featuring a non-Fermi-liquid temperature dependence. In contrast, for the corresponding Fe site in the hcp phase, we predict a weakly correlated Fermi-liquid state with a temperature-independent local susceptibility and a quadratic temperature dependence of Gamma. The iron sites with nickel atoms in the local environment exhibit behavior in the range between those two extreme cases, with the strength of correlations gradually increasing along the hcp-fcc-bcc sequence. Further, the intersite magnetic interactions in the bcc and hcp phases are also strongly affected by the presence of Ni nearest neighbors. The sensitivity to the local environment is related to modifications of the Fe partial density of states due to mixing with Ni 3d states.</p>","","","","","","","","","","","","","2015-06-26","2015-06-26","2017-12-04","","","4","","2","","","","","","false","","","" "825126","Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Högberg, Hans [hanho47] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Armiento, Rickard [ricar47] [0000-0002-5571-0814] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Rosén, Johanna [johro07] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Hultman, Lars [larhu75] [0000-0002-2837-3656] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska fakulteten [872902])","A theoretical investigation of mixing thermodynamics, age-hardening potential, and electronic structure of ternary (M1-xMxB2)-M-1-B-2 alloys with AlB2 type structure","Artikel i tidskrift","Refereegranskat","eng","Scientific Reports","2045-2322","2045-2322","published","5","","","","","2015","","","","Nature Publishing Group: Open Access Journals - Option C / Nature Publishing Group","","","","","","","10.1038/srep09888","000355215100001","25970763","","urn:nbn:se:liu:diva-119589","","","","Fysik (103)","","","<p>Funding Agencies|Swedish Research Council (VR) [621-2011-4417, 621-2011-4249]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; Knut and Alice Wallenberg Foundation; ERC [258509]</p>","<p>Transition metal diborides are ceramic materials with potential applications as hard protective thin films and electrical contact materials. We investigate the possibility to obtain age hardening through isostructural clustering, including spinodal decomposition, or ordering-induced precipitation in ternary diboride alloys. By means of first-principles mixing thermodynamics calculations, 45 ternary (M1-xMxB2)-M-1-B-2 alloys comprising (MB2)-B-i (M-i = Mg, Al, Sc, Y, Ti, Zr, Hf, V, Nb, Ta) with AlB2 type structure are studied. In particular Al1-xTixB2 is found to be of interest for coherent isostructural decomposition with a strong driving force for phase separation, while having almost concentration independent a and c lattice parameters. The results are explained by revealing the nature of the electronic structure in these alloys, and in particular, the origin of the pseudogap at E-F in TiB2, ZrB2, and HfB2.</p>","","","","","","","","","","","","","2015-06-22","2015-06-23","2017-12-04","http://liu.diva-portal.org/smash/get/diva2:825126/FULLTEXT01.pdf","","5","","1","","","","","","false","","","" "824843","Ponomareva, A. V. (National University of Science and Technology, Russia);Gornostyrev, Yu. N. (Institute Quantum Mat Science, Russia; Russian Academic Science, Russia);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (National University of Science and Technology, Russia)","Energy of interaction between carbon impurities in paramagnetic gamma-iron","Artikel i tidskrift","Refereegranskat","eng","Journal of Experimental and Theoretical Physics","1063-7761","1090-6509","published","120","4","","716","724","2015","","","","M A I K Nauka - Interperiodica","","","","","","","10.1134/S1063776115020193","000355216500016","","","urn:nbn:se:liu:diva-119596","","","","Fysik (103)","","","<p>Funding Agencies|Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Swedish Foundation for Strategic Research (SSF) [10-0026]; Russian Foundation for Basic Research [13-02-00-606a]</p>","<p>The energies of interaction between carbon impurity atoms in paramagnetic fcc iron (austenite) are calculated using electron density functional theory. Point defects in the paramagnetic matrix are described using a statistical approach that takes into account local magnetic fluctuations and atomic relaxation in the environment of impurity atoms. It is shown that, in addition to local deformations, magnetism significantly contributes to the energies of dissolution and interaction of carbon atoms. The values of the carbon-carbon interaction energy are indicative of a significant repulsion between these atoms in the first and second coordination spheres. The results of calculations are consistent with estimates obtained from experimental data on the activity of carbon impurity atoms in iron.</p>","","","","","","","","","","","","","2015-06-22","2015-06-22","2017-12-04","","","3","","1","","","","","","false","","","" "841488","Raza, Zamaan [zamra51] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Shulumba, Nina [ninsh46] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282]) (University of Saarland, Germany);Nuala, Mai Caffrey [nuaca84] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Dubrovinsky, Leonid (University of Bayreuth, Germany);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (NUST MISIS, Russia; Tomsk State University, Russia)","First-principles calculations of properties of orthorhombic iron carbide Fe₇C₃ at the Earths core conditions","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","1550-235X","published","91","21","","","","2015","","","","American Physical Society","","","","","","","10.1103/PhysRevB.91.214112","000356791500001","","","urn:nbn:se:liu:diva-120164","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Research Council (VR) [621-2011-4426]; SSF programs ""Multifilms""; SRL [10-0026]; Erasmus Mundus Joint European Doctoral Programme DocMASE; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Tomsk State University Academic D. I. Mendeleev Fund Program [8.1.18.2015]; Swedish Foundation for Strategic Research (SSF) program FUNCASE</p>","<p>A recently discovered phase of orthorhombic iron carbide o-Fe7C3 [Prescher et al., Nat. Geosci. 8, 220 (2015)] is assessed as a potentially important phase for interpretation of the properties of the Earths core. In this paper, we carry out first-principles calculations on o-Fe7C3, finding properties to be in broad agreement with recent experiments, including a high Poissons ratio (0.38). Our enthalpy calculations suggest that o-Fe7C3 is more stable than Eckstrom-Adcock hexagonal iron carbide (h-Fe7C3) below approximately 100 GPa. However, at 150 GPa, the two phases are essentially degenerate in terms of Gibbs free energy, and further increasing the pressure towards Earths core conditions stabilizes h-Fe7C3 with respect to the orthorhombic phase. Increasing the temperature tends to stabilize the hexagonal phase at 360 GPa, but this trend may change beyond the limit of the quasiharmonic approximation.</p>","","","","","","","","","","","","","2015-07-13","2015-07-13","2017-12-04","http://liu.diva-portal.org/smash/get/diva2:841488/FULLTEXT01.pdf","","5","","2","urn:nbn:se:liu:diva-122949","","","","214112","false","","","" "841482","Falk, Abram L. (University of Chicago, IL 60637 USA; IBM TJ Watson Research Centre, NY 10598 USA);Klimov, Paul V. (University of Chicago, IL 60637 USA; University of Calif Santa Barbara, CA 93106 USA; Hungarian Academic Science, Hungary);Ivády, Viktor [vikiv58] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Hungary);Szasz, Krisztian (Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Hungary; Eotvos Lorand University, Hungary);Christle, David J. (University of Chicago, IL 60637 USA; University of Calif Santa Barbara, CA 93106 USA; Hungarian Academic Science, Hungary);Koehl, William F. (University of Chicago, IL 60637 USA);Gali, Adam (Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Hungary; Budapest University of Technology and Econ, Hungary);Awschalom, David D. (University of Chicago, IL 60637 USA)","Optical Polarization of Nuclear Spins in Silicon Carbide","Artikel i tidskrift","Refereegranskat","eng","Physical Review Letters","0031-9007","1079-7114","published","114","24","","247603","","2015","","","","American Physical Society","","","","","","","10.1103/PhysRevLett.114.247603","000356407600010","","","urn:nbn:se:liu:diva-120166","","","","Fysik (103)","","","<p>Funding Agencies|Air Force Office of Scientific Research (AFOSR); AFOSR Multidisciplinary Research Program of the University Research Initiative; National Science Foundation; Material Research Science and Engineering Center; Knut and Alice Wallenberg Foundation ""Isotopic Control for Ultimate Materials Properties""; Lendulet program of the Hungarian Academy of Sciences; National Supercomputer Center in Sweden</p>","<p>We demonstrate optically pumped dynamic nuclear polarization of Si-29 nuclear spins that are strongly coupled to paramagnetic color centers in 4H- and 6H-SiC. The 99% +/- 1% degree of polarization that we observe at room temperature corresponds to an effective nuclear temperature of 5 mu K. By combining ab initio theory with the experimental identification of the color centers optically excited states, we quantitatively model how the polarization derives from hyperfine-mediated level anticrossings. These results lay a foundation for SiC-based quantum memories, nuclear gyroscopes, and hyperpolarized probes for magnetic resonance imaging.</p>","","","","","","","","","","","","","2015-07-13","2015-07-13","2017-12-04","http://liu.diva-portal.org/smash/get/diva2:841482/FULLTEXT01.pdf","","8","","2","urn:nbn:se:liu:diva-131853","","","","","false","","","" "843005","Mendonca, J. T. (Institute Super Tecn, Portugal);Stenflo, Lennart [lenst65] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Acoustic-gravity waves in the atmosphere: from Zakharov equations to wave-kinetics","Artikel i tidskrift","Refereegranskat","eng","Physica Scripta","0031-8949","1402-4896","published","90","5","","055001","","2015","","","","IOP Publishing: Hybrid Open Access","","","","","","","10.1088/0031-8949/90/5/055001","000356498700016","","","urn:nbn:se:liu:diva-120293","","","acoustic-gravity waves; Zakharov equations; Wigner function","Fysik (103)","","","<p>Funding Agencies|International Space Science Institute in Bern (Switzerland)</p>","<p>We develop a wave-kinetic description of acoustic-gravity (AG) waves in the atmosphere. In our paper the high frequency spectrum of waves is described as a gas of quasi-particles. Starting from the Zakharov-type of equations, where coupling between fast and slow density perturbations is considered, we derive the corresponding wave-kinetic equations, written in terms of an appropriate Wigner function. This provides an alternative description for the nonlinear interaction between the two dispersion branches of the AG waves.</p>","","","","","","","","","","","","","2015-07-24","2015-07-24","2017-12-04","http://liu.diva-portal.org/smash/get/diva2:843005/FULLTEXT01.pdf","","2","","1","","","","","","false","","","" "842655","Romero, A. H. (W Virginia University, WV 26506 USA; Max Planck Institute Mikrostrukturphys, Germany);Gross, E. K. U. (Max Planck Institute Mikrostrukturphys, Germany);Verstraete, M. J. (University of Liege, Belgium; University of Liege, Belgium);Hellman, Olle [olohe96] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (CALTECH, CA 91125 USA)","Thermal conductivity in PbTe from first principles","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","1550-235X","published","91","21","","214310","","2015","","","","American Physical Society","","","","","","","10.1103/PhysRevB.91.214310","000357020900002","","","urn:nbn:se:liu:diva-120224","","","","Fysik (103)","","","<p>Funding Agencies|Marie Curie Actions from the European Union [PIIFR-GA-2011-911070]; American Chemical Society Petroleum Research Fund [54075-ND10]; National Science Foundation [1434897]; Action de Recherches Concertees (ARC) from the Communaute Francaise de Belgique [10/15-03]; EU FP7 [RI-283493, RI-312763]; Swedish Research Council (VR) program [637-2013-7296]</p>","<p>We investigate the harmonic and anharmonic contributions to the phonon spectrum of lead telluride and perform a complete characterization of how thermal properties of PbTe evolve as temperature increases. We analyze the thermal resistivitys variationwith temperature and clarify misconceptions about existing experimental literature. The resistivity initially increases sublinearly because of phase space effects and ultra strong anharmonic renormalizations of specific bands. This effect is the strongest factor in the favorable thermoelectric properties of PbTe, and it explains its limitations at higher T. This quantitative prediction opens the prospect of phonon phase space engineering to tailor the lifetimes of crucial heat carrying phonons by considering different structure or nanostructure geometries. We analyze the available scattering volume between TO and LA phonons as a function of temperature and correlate its changes to features in the thermal conductivity.</p>","","","","","","","","","","","","","2015-07-20","2015-07-21","2017-12-04","http://liu.diva-portal.org/smash/get/diva2:842655/FULLTEXT01.pdf","","4","","2","","","","","","false","","","" "851813","Nuala, Mai Caffrey [nuaca84] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Armiento, Rickard [ricar47] [0000-0002-5571-0814] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Yakimova, Rositsa [rosia15] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (NUST MISIS, Russia; Tomsk State University, Russia)","Charge neutrality in epitaxial graphene on 6H-SiC(0001) via nitrogen intercalation","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","1550-235X","published","92","8","","","","2015","","","","American Physical Society","","","","","","","10.1103/PhysRevB.92.081409","000359861600002","","","urn:nbn:se:liu:diva-121104","","","","Den kondenserade materiens fysik (10304);Oorganisk kemi (10404)","","","<p>Funding Agencies|European Union [604391]; Swedish Research Council (VR) [621-2011-4426]; Swedish Foundation for Strategic Research (SSF) program SRL Grant [10-0026]; VR Grant [621-2011-4249]; Linnaeus Environment at Linkoping on Nanoscale Functional Materials (LiLi-NFM) - VR; Grant of Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Tomsk State University Academic D. I. Mendeleev Fund Program [8.1.18.2015]</p>","<p>The electronic properties of epitaxial graphene grown on SiC(0001) are known to be impaired relative to those of freestanding graphene. This is due to the formation of a carbon buffer layer between the graphene layers and the substrate, which causes the graphene layers to become strongly n-doped. Charge neutrality can be achieved by completely passivating the dangling bonds of the clean SiC surface using atomic intercalation. So far, only one element, hydrogen, has been identified as a promising candidate. We show, using first-principles density functional calculations, how it can also be accomplished via the growth of a thin layer of silicon nitride on the SiC surface. The subsequently grown graphene layers display the electronic properties associated with charge neutral graphene. We show that the surface energy of this structure is considerably lower than that of others with intercalated atomic nitrogen and determine how its stability depends on the N-2 chemical potential.</p>","","","","","","","","","","","","","2015-09-07","2015-09-07","2017-12-04","http://liu.diva-portal.org/smash/get/diva2:851813/FULLTEXT01.pdf","","4","","2","","","","","081409","false","","","" "812558","Gällström, Andreas [andga78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Magnusson, Björn [bjoma90] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Leone, Stefano [stele19] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Kordina, Olof [ollko50] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Son, Nguyen Tien [nguso90] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Ivády, Viktor [vikiv58] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Wigner Research Center for Physics, Hungarian Academy of Sciences, Hungary);Gali, Adam [adaga79] (Wigner Research Center for Physics, Hungarian Academy of Sciences, Budapest Hungary; Department of Atomic Physics, Budapest University of Technology and Economics, Budapest, Hungary);Abrikosov, Igor A. [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Materials Modeling and Development Laboratory, NUST “MISIS,” Moscow, Russia; LACOMAS Laboratory, Tomsk State University, Tomsk, Russia);Janzén, Erik [erija14] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Ivanov, Ivan G. [ivaiv28] [0000-0003-1000-0437] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Optical properties and Zeeman spectroscopy of niobium in silicon carbide","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","1550-235X","published","92","7","","1","14","2015","","","","American Physical Society","","","","","","","10.1103/PhysRevB.92.075207","000362204100001","","","urn:nbn:se:liu:diva-117972","","","","Teoretisk kemi (10407);Annan fysik (10399)","","","<p>At the time for thesis presentation publication was in status: Manuscript</p><p>Funding Agencies|Knut and Alice Wallenberg Foundation; Lendulet program of the Hungarian Academy of Sciences; Hungarian OTKA Project [K101819]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Tomsk State University Academic D. I. Mendeleev Fund Program [8.1.18.2015]</p>","<p>The optical signature of niobium in the low-temperature photoluminescence spectra of three common polytypes of SiC (4H, 6H, and 15R) is observed and confirms the previously suggested concept that Nb occupies preferably the Si-C divacancy with both Si and C at hexagonal sites. Using this concept we propose a model considering a Nb-bound exciton, the recombination of which is responsible for the observed luminescence. The exciton energy is estimated using first-principles calculation and the result is in very good agreement with the experimentally observed photon energy in 4H SiC at low temperature. The appearance of six Nb-related lines in the spectra of the hexagonal 4H and 6H polytypes at higher temperatures is tentatively explained on the grounds of the proposed model and the concept that the Nb center can exist in both C1h and C3v symmetries. The Zeeman splitting of the photoluminescence lines is also recorded in two different experimental geometries and the results are compared with theory based on phenomenological Hamiltonians. Our results show that Nb occupying the divacancy at the hexagonal site in the studied SiC polytypes behaves like a deep acceptor.</p>","","","","","","","","","","","","","2015-05-19","2015-05-19","2017-12-04","http://liu.diva-portal.org/smash/get/diva2:812558/FULLTEXT01.pdf","","10","","2","urn:nbn:se:liu:diva-117978","","","","075207","true","","","" "811680","Sernelius, Bo E. [bose02] [0000-0002-6281-868X] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]) (Theoretical Physics)","Casimir effects in systems containing 2D layers such as graphene and 2D electron gases","Artikel i tidskrift","Refereegranskat","eng","Journal of Physics: Condensed Matter","0953-8984","1361-648X","published","27","21","","214017","","2015","","","","Institute of Physics Publishing (IOPP)","","","","","","","10.1088/0953-8984/27/21/214017","000354390300018","25965400","","urn:nbn:se:liu:diva-117886","","","Casimir;2D;graphene;normal modes;Feynman diagrams;zero-point energy","Övrig annan teknik (21199)","","","","<p>We present a variety of methods to derive the Casimir interaction in planar systems containing2D layers. Examples where this can be of use is graphene, graphene-like layers and 2Delectron gases. We present results for two free standing layers and for one layer above asubstrate. The results can easily be extended to systems with a larger number of layers.</p>","","","","","","","","","","","","","2015-05-12","2015-05-12","2017-12-04","http://liu.diva-portal.org/smash/get/diva2:811680/FULLTEXT01.pdf","","1","","1","","","","","","true","","","" "802654","Arapan, Sergiu (National Institute Mat Science, Japan; Moldavian Academic Science, Moldova);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Skorodumova, Natalia V. (KTH Royal Institute Technology, Sweden; Uppsala University, Sweden)","Volume-dependent electron localization in ceria","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","1550-235X","published","91","12","","125108","","2015","","","","American Physical Society","","","","","","","10.1103/PhysRevB.91.125108","000350500100003","","","urn:nbn:se:liu:diva-116953","","","","Fysik (103)","","","<p>Funding Agencies|Swedish Research Council [2014-4750]; Swedish Energy Agency (STEM); Carl Tryggers Foundation; LiLi-NFM; Swedish Government Strategic Research Area Grant in Materials Science</p>","<p>We have performed a numerical study of the process of electron localization in reduced ceria. Our results show that different localized charge distributions can be attained in a bulk system by varying the lattice parameter. We demonstrate that the effect of electron localization is mainly determined by lattice relaxation and an accurate account for the effects of electronic correlation is necessary to achieve localized charge distribution.</p>","","","","","","","","","","","","","2015-04-10","2015-04-13","2017-12-04","http://liu.diva-portal.org/smash/get/diva2:802654/FULLTEXT01.pdf","","3","","2","","","","","","false","","","" "802619","Szasz, Krisztian (Hungarian Academic Science, Hungary; Eotvos Lorand University, Hungary);Ivády, Viktor [vikiv58] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]) (Hungarian Academic Science, Hungary);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]) (National University of Science and Technology MISIS, Russia; Tomsk State University, Russia);Janzén, Erik [erija14] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska högskolan [1751]);Bockstedte, Michel (University of Erlangen Nurnberg, Germany; Salzburg University, Austria; University of Basque Country, Spain);Gali, Adam (Hungarian Academic Science, Hungary; Budapest University of Technology and Econ, Hungary)","Spin and photophysics of carbon-antisite vacancy defect in 4H silicon carbide: A potential quantum bit","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","1550-235X","published","91","12","","121201","","2015","","","","American Physical Society","","","","","","","10.1103/PhysRevB.91.121201","000351038400004","","","urn:nbn:se:liu:diva-116950","","","","Fysik (103);Kemi (104)","","","<p>Funding Agencies|MTA Lendulet program of Hungarian Academy of Sciences; Knut and Alice Wallenberg Foundation; Swedish Foundation for Strategic Research program SRL [10-0026]; SNIC [001/12-275, 2013/1-331]; US Department of Energy, Office of Science, Office of Basic Energy Sciences [DE-AC02-06CH11357]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Tomsk State University Academic D. I. Mendeleev Fund Program</p>","<p>Silicon carbide with engineered point defects is considered as very promising material for the next generation devices, with applications ranging from electronics and photonics to quantum computing. In this context, we investigate the spin physics of the carbon antisite-vacancy pair that in its positive charge state enables a single photon source. We find by hybrid density functional theory and many-body perturbation theory that the neutral defect possesses a high spin ground state in 4H silicon carbide and provide spin-resonance signatures for its experimental identification. Our results indicate the possibility for the coherent manipulation of the electron spin by optical excitation of this defect at telecom wavelengths, and suggest the defect as a candidate for an alternative solid state quantum bit.</p>","","","","","","","","","","","","","2015-04-10","2015-04-13","2017-12-04","http://liu.diva-portal.org/smash/get/diva2:802619/FULLTEXT01.pdf","","6","","2","","","","","","false","","","" "802610","Mozafari, Elham [elhmo04] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk kemi [16855]) (Linköpings universitet [276], Tekniska högskolan [1751]);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]);Steneteg, Peter [petst55] (Linköpings universitet [276], Institutionen för teknik och naturvetenskap [296], Medie- och Informationsteknik [6850]) (Linköpings universitet [276], Tekniska högskolan [1751]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]) (NUST MISIS, Russia; Tomsk State University, Russia)","Role of N defects in paramagnetic CrN at finite temperatures from first principles","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","1550-235X","published","91","9","","094101","","2015","","","","American Physical Society","","","","","","","10.1103/PhysRevB.91.094101","000350994400001","","","urn:nbn:se:liu:diva-116954","","","","Fysik (103);Elektroteknik och elektronik (202)","","","<p>Funding Agencies|Swedish Research Council (VR) [621-2011-4426]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Tomsk State University Academic D. I. Mendeleev Fund Program; VR [621-2011-4417]</p>","<p>Simulations of defects in paramagnetic materials at high temperature constitute a formidable challenge to solid-state theory due to the interaction of magnetic disorder, vibrations, and structural relaxations. CrN is a material where these effects are particularly large due to a strong magnetolattice coupling and a tendency for deviations from the nominal 1: 1 stoichiometry. In this work, we present a first-principles study of nitrogen vacancies and nitrogen interstitials in CrN at elevated temperature. We report on formation energetics, the geometry of interstitial nitrogen dimers, and the impact on the electronic structure caused by the defects. We find a vacancy formation energy of 2.28 eV with a small effect of temperature, i.e., a formation energy for N interstitial in the form of a less than 111 greater than -oriented split bond of 3.77 eV with an increase to 3.97 at 1000 K. Vacancies are found to add three electrons, while split-bond interstitial adds one electron to the conduction band. The band gap of defect-free CrN is smeared out due to vibrations, although it is difficult to draw a conclusion about the exact temperature at which the band gap closes from our calculations. However, it is clear that at 900 K there is a nonzero density of electronic states at the Fermi level. At 300 K, our results indicate a border case where the band gap is about to close.</p>","","","","","","","","","","","","","2015-04-10","2015-04-13","2017-12-04","http://liu.diva-portal.org/smash/get/diva2:802610/FULLTEXT01.pdf","","4","","2","urn:nbn:se:liu:diva-130517","","","","","false","","","" "798857","Belov, Maxim [maxbe65] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]) (National University of Science and Technology MISIS, Russia);Syzdykova, A. B. (National University of Science and Technology MISIS, Russia; Al Farabi Kazakh National University, Kazakhstan);Kh Vekilov, Yu (National University of Science and Technology MISIS, Russia);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751])","Hydrogen in palladium: Anharmonicity of lattice dynamics from first principles","Artikel i tidskrift","Refereegranskat","eng","Physics of the solid state","1063-7834","1090-6460","published","57","2","","260","265","2015","","","","M A I K Nauka - Interperiodica","","","","","","","10.1134/S1063783415020067","000349970800007","","","urn:nbn:se:liu:diva-116526","","","","Fysik (103)","","","<p>Funding Agencies|Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Program for Enhancing the Competitiveness of the National University of Science and Technology ""MISIS"" World Leading Research and Educational Centers; Russian Foundation for Basic Research [13-02-00844]; Swedish Foundation for Strategic Research (SSF) (SRL) [10-0026]</p>","<p>The interaction potentials of the palladium and hydrogen sublattices at different hydrogen concentrations have been obtained in terms of the density functional theory and ab initio pseudopotentials. It has been shown that the anharmonicity of this interaction depends on the hydrogen concentration. The phonon spectrum of palladium hydride PdH has been calculated in the harmonic approximation and taking into account the anharmonic effects. The temperature-dependent effective potential technique accounting for the anharmonic effects of lattice vibrations has been described.</p>","","","","","","","","","","","","","2015-03-27","2015-03-27","2017-12-04","","","4","","1","","","","","","true","","","" "802576","Bostrom, M. (University of Oslo, Norway; Norwegian University of Science and Technology, Norway);Thiyam, P. (Royal Institute Technology, Sweden);Persson, C. (University of Oslo, Norway; Royal Institute Technology, Sweden; University of Oslo, Norway);Parsons, D. F. (Australian National University, Australia);Buhmann, S. Y. (University of Freiburg, Germany; University of Freiburg, Germany);Brevik, I. (Norwegian University of Science and Technology, Norway);Sernelius, Bo [bose02] [0000-0002-6281-868X] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751])","Non-perturbative theory of dispersion interactions","Artikel i tidskrift","Refereegranskat","eng","Physica Scripta","0031-8949","1402-4896","published","90","3","","035405","","2015","","","","IOP Publishing: Hybrid Open Access","","","","","","","10.1088/0031-8949/90/3/035405","000350866700023","","","urn:nbn:se:liu:diva-116966","","","fluctuation forces; non-perturbative theory; van der Waals interactions","Fysik (103)","","","<p>Funding Agencies|Research Council of Norway [221469]; European Commission; German Research Council [BU 1803/3-1]; Freiburg Institute for Advanced Studies; Swedish Research Council [C0485101]</p>","<p>Some open questions exist with fluctuation-induced forces between extended dipoles. Conventional intuition derives from large-separation perturbative approximations to dispersion force theory. Here, we present a full non-perturbative theory. In addition, we discuss how one can take into account finite dipole size corrections. It is of fundamental value to investigate the limits of validity of the perturbative dispersion force theory.</p>","","","","","","","","","","","","","2015-04-10","2015-04-13","2017-12-04","http://liu.diva-portal.org/smash/get/diva2:802576/FULLTEXT01.pdf","","7","","1","","","","","","false","","","" "795358","Cao, C. (Physics Department, Illinois Institute of Technology, Chicago, Illinois, USA, Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA );Tao, R. (Physics Department, University of Illinois at Chicago, Chicago, Illinois, USA);Ford, D.C. (Materials Science Division, Argonne National Laboratory, Argonne, Illinois USA);Klie, R. (Physics Department, University of Illinois at Chicago, Chicago, Illinois, USA);Proslier, T. (Materials Science Division, Argonne National Laboratory, Argonne, Illinois, USA);Cooley, L. (Superconducting Materials Department, Technical Division, !Fermi National Accelerator Laboratory, Batavia, Illinois, USA);Dzyuba, A. (Superconducting Materials Department, Technical Division, !Fermi National Accelerator Laboratory, Batavia, Illinois, USA);Zapol, P. (Materials Science Division, Argonne National Laboratory, Argonne, Illinois, USA);Warren, M. (Physics Department, Illinois Institute of Technology, Chicago, Illinois, USA);Lind, Hans [hanli61] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Zasadzinski, J. F. (Physics Department, Illinois Institute of Technology, Chicago, Illinois, USA)","Giant two-phonon Raman scattering from nanoscale NbC precipitates in Nb","Artikel i tidskrift","Refereegranskat","eng","Physical Review B Condensed Matter","0163-1829","1095-3795","published","91","9","","","","2015","","","","American Physical Society","","","","","","","10.1103/PhysRevB.91.094302","000351036900002","","","urn:nbn:se:liu:diva-115403","","","","Fysik (103)","","","<p>The authors thank G. Ciovati of Jefferson Laboratory for supplying Nb samples used in this study. Calculations (H.L.) were performed with financial support by the SSF-project Designed multicomponent coatings, MultiFilms and the Swedish Research Council. Calculations were carried out at the Swedish National Infrastructure for Computing (SNIC), Argonne LCRC and Argonne Center for Nanoscale Materials. The work at Argonne National Laboratory and the use of the Center for Nanoscale Materials and the Electron Microscopy center at Argonne National Laboratory were supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-06CH11357. This work was also supported by the Department of Energy, Office of Science, Office of High Energy Physics, early career award FWP#50335 to T.P.</p>","<p>High purity niobium (Nb), subjected to the processing methods used in the fabrication of superconducting RF cavities, displays micron-sized surface patches containing excess carbon. High-resolution transmission electron microscopy and electron energy-loss spectroscopy measurements are presented which reveal the presence of nanoscale NbC coherent precipitates in such regions. Raman backscatter spectroscopy on similar surface regions exhibit spectra consistent with the literature results on bulk NbC but with significantly enhanced two-phonon scattering. The unprecedented strength and sharpness of the two-phonon signal has prompted a theoretical analysis, using density functional theory (DFT), of phonon modes in NbC for two different interface models of the coherent precipitate. One model leads to overall compressive strain and a comparison to ab-initio calculations of phonon dispersion curves under uniform compression of the NbC shows that the measured two-phonon peaks are linked directly to phonon anomalies arising from strong electron-phonon interaction. Another model of the extended interface between Nb and NbC, studied by DFT, gives insight into the frequency shifts of the acoustic and optical mode density of states measured by first order Raman. The exact origin of the stronger two-phonon response is not known at present but it suggests the possibility of enhanced electron-phonon coupling in transition metal carbides under strain found either in the bulk NbC inclusions or at their interfaces with Nb metal. Preliminary tunneling studies using a point contact method show some energy gaps larger than expected for bulk NbC.</p>","","","","","","","","","","","","","2015-03-16","2015-03-16","2017-12-04","http://liu.diva-portal.org/smash/get/diva2:795358/FULLTEXT01.pdf","","11","","0","urn:nbn:se:liu:diva-115405","","","","094302","true","","","" "795085","Di Meo, Florent [flodi20] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk kemi [16855]) (Linköpings universitet [276], Tekniska högskolan [1751]);Pedersen, Morten [morpe47] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]) (University of Southern Denmark, Denmark);Rubio-Magnieto, Jenifer (University of Mons UMONS, Belgium);Surin, Mathieu (University of Mons UMONS, Belgium);Linares, Mathieu [matli20] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk kemi [16855]) (Linköpings universitet [276], Tekniska högskolan [1751]) (University of Mons UMONS, Belgium);Norman, Patrick [patno81] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk kemi [16855]) (Linköpings universitet [276], Tekniska högskolan [1751])","DNA Electronic Circular Dichroism on the Inter-Base Pair Scale: An Experimental Theoretical Case Study of the AT Homo-Oligonucleotide","Artikel i tidskrift","Refereegranskat","eng","Journal of Physical Chemistry Letters","1948-7185","1948-7185","published","6","3","","355","359","2015","","","","American Chemical Society","","","","","","","10.1021/jz502696t","000349137400009","","","urn:nbn:se:liu:diva-115321","","","","Fysik (103)","","","<p>Funding Agencies|Swedish Research Council [621-2014-4646]; FNRS (Belgium) [2.4615.11-BINDER]</p>","<p>A successful elucidation of the near-ultraviolet electronic circular dichroism spectrum of a short double-stranded DNA is reported. Time-dependent density functional theory methods are shown to accurately predict spectra and assign bands on the microscopic base-pair scale, a finding that opens the field for using circular dichroism spectroscopy as a sensitive nanoscale probe of DNA to reveal its complex interactions with the environment.</p>","","","","","","","","","","","","","2015-03-13","2015-03-13","2017-12-04","","","6","","1","urn:nbn:se:liu:diva-127496","","","","","false","","","" "794102","Meng, Fanqi (Goethe University of Frankfurt, Germany);Thomson, Mark D. (Goethe University of Frankfurt, Germany);Sernelius, Bo [bose02] [0000-0002-6281-868X] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Joerger, Michael (Bruker Opt GmbH, Germany);Roskos, Hartmut G. (Goethe University of Frankfurt, Germany)","Ultrafast dynamic conductivity and scattering rate saturation of photoexcited charge carriers in silicon investigated with a midinfrared continuum probe","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","1550-235X","published","91","7","","075201","","2015","","","","American Physical Society","","","","","","","10.1103/PhysRevB.91.075201","000349247900002","","","urn:nbn:se:liu:diva-114978","","","","Fysik (103)","","","<p>Funding Agencies|Deutsche Forschungsgemeinschaft (DFG)</p>","<p>We employ ultrabroadband terahertz-midinfrared probe pulses to characterize the optical response of photoinduced charge-carrier plasmas in high-resistivity silicon in a reflection geometry, over a wide range of excitation densities (10(15)-10(19) cm(-3)) at room temperature. In contrast to conventional terahertz spectroscopy studies, this enables one to directly cover the frequency range encompassing the resultant plasma frequencies. The intensity reflection spectra of the thermalized plasma, measured using sum-frequency (up-conversion) detection of the probe pulses, can be modeled well by a standard Drude model with a density-dependent momentum scattering time of similar to 200 fs at low densities, reaching similar to 20 fs for densities of similar to 10(19) cm(-3), where the increase of the scattering rate saturates. This behavior can be reproduced well with theoretical results based on the generalized Drude approach for the electron-hole scattering rate, where the saturation occurs due to phase-space restrictions as the plasma becomes degenerate. We also study the initial subpicosecond temporal development of the Drude response and discuss the observed rise in the scattering time in terms of initial charge-carrier relaxation, as well as the optical response of the photoexcited sample as predicted by finite-difference time-domain simulations.</p>","","","","","","","","","","","","","2015-03-06","2015-03-10","2017-12-04","http://liu.diva-portal.org/smash/get/diva2:794102/FULLTEXT01.pdf","","5","","2","","","","","","false","","","" "791633","Sangiovanni, Davide [davsa82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]);Steneteg, Peter [petst55] (Linköpings universitet [276], Institutionen för teknik och naturvetenskap [296], Medie- och Informationsteknik [6850]) (Linköpings universitet [276], Tekniska högskolan [1751]);Hultman, Lars [larhu75] [0000-0002-2837-3656] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]) (National University of Science and Technology, Russia; Tomsk State University, Russia)","Nitrogen vacancy, self-interstitial diffusion, and Frenkel-pair formation/dissociation in B1 TiN studied by ab initio and classical molecular dynamics with optimized potentials","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","1550-235X","published","91","5","","054301","","2015","","","","American Physical Society","","","","","","","10.1103/PhysRevB.91.054301","000348872600002","","","urn:nbn:se:liu:diva-114567","","","","Fysik (103);Elektroteknik och elektronik (202)","","","<p>Funding Agencies|Knut and Alice Wallenberg Foundation [2011.0094]; Swedish Research Council (VR) Linkoping Linnaeus Initiative LiLi-NFM [2008-6572]; Swedish Government Strategic Research Area Grant in Materials Science on Advanced Functional Materials through Swedens innovation agency VINNOVA [MatLiU 2009-00971]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Tomsk State University Academic D. I. Mendeleev Fund Program</p>","<p>We use ab initio and classical molecular dynamics (AIMD and CMD) based on the modified embedded-atom method (MEAM) potential to simulate diffusion of N vacancy and N self-interstitial point defects in B1 TiN. TiN MEAM parameters are optimized to obtain CMD nitrogen point-defect jump rates in agreement with AIMD predictions, as well as an excellent description of TiNx (similar to 0.7 less than x less than= 1) elastic, thermal, and structural properties. We determine N dilute-point-defect diffusion pathways, activation energies, attempt frequencies, and diffusion coefficients as a function of temperature. In addition, the MD simulations presented in this paper reveal an unanticipated atomistic process, which controls the spontaneous formation of N self-interstitial/N vacancy (N-I/N-V) pairs (Frenkel pairs), in defect-free TiN. This entails that the N lattice atom leaves its bulk position and bonds to a neighboring N lattice atom. In most cases, Frenkel-pair N-I and N-V recombine within a fraction of ns; similar to 50% of these processes result in the exchange of two nitrogen lattice atoms (N-N-Exc). Occasionally, however, Frenkel-pair N-interstitial atoms permanently escape from the anion vacancy site, thus producing unpaired N-I and N-V point defects.</p>","","","","","","","","","","","","","2015-02-26","2015-03-02","2017-12-04","http://liu.diva-portal.org/smash/get/diva2:791633/FULLTEXT01.pdf","","5","","2","","","","","","false","","","" "791634","Mei, A. B. (University of Illinois, IL 61801 USA; University of Illinois, IL 61801 USA);Hellman, Olle [olohe96] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]) (CALTECH, CA 91125 USA);Wireklint, N. (Chalmers, Sweden);Schlepuetz, C. M. (Argonne National Lab, IL 60439 USA);Sangiovanni, Davide [davsa82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]);Rockett, A. (University of Illinois, IL 61801 USA; University of Illinois, IL 61801 USA);Hultman, Lars [larhu75] [0000-0002-2837-3656] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]);Petrov, Ivan [ivape26] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]) (University of Illinois, IL 61801 USA; University of Illinois, IL 61801 USA);Greene, Joseph E [josgr17] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]) (University of Illinois, IL 61801 USA; University of Illinois, IL 61801 USA)","Dynamic and structural stability of cubic vanadium nitride","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","1550-235X","published","91","5","","054101","","2015","","","","American Physical Society","","","","","","","10.1103/PhysRevB.91.054101","000348872600001","","","urn:nbn:se:liu:diva-114566","","","","Fysik (103)","","","<p>Funding Agencies|Swedish Research Council (VR) program [637-2013-7296, 2014-5790, 2009-00971, 2013-4018]; Swedish Government Strategic Research Area Grant in Materials Science [SFO Mat-LiU 2009-00971]; DOE Office of Science by Argonne National Laboratory [DE-AC02-06CH11357]</p>","<p>Structural phase transitions in epitaxial stoichiometric VN/MgO(011) thin films are investigated using temperature-dependent synchrotron x-ray diffraction (XRD), selected-area electron diffraction (SAED), resistivity measurements, high-resolution cross-sectional transmission electron microscopy, and ab initio molecular dynamics (AIMD). At room temperature, VN has the B1 NaCl structure. However, below T-c = 250 K, XRD and SAED results reveal forbidden (00l) reflections of mixed parity associated with a noncentrosymmetric tetragonal structure. The intensities of the forbidden reflections increase with decreasing temperature following the scaling behavior I proportional to (T-c - T)(1/2). Resistivity measurements between 300 and 4 K consist of two linear regimes resulting from different electron/phonon coupling strengths in the cubic and tetragonal-VN phases. The VN transport Eliashberg spectral function alpha F-2(tr)(h omega), the product of the phonon density of states F(h omega) and the transport electron/phonon coupling strength alpha(2)(tr)(h omega), is determined and used in combination with AIMD renormalized phonon dispersion relations to show that anharmonic vibrations stabilize the NaCl structure at T greater than T-c. Free-energy contributions due to vibrational entropy, often neglected in theoretical modeling, are essential for understanding the room-temperature stability of NaCl-structure VN, and of strongly anharmonic systems in general.</p>","","","","","","","","","","","","","2015-02-26","2015-03-02","2017-12-04","http://liu.diva-portal.org/smash/get/diva2:791634/FULLTEXT01.pdf","","10","","2","","","","","","false","","",""