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 "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","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","2016-12-27","","","2","","1","","","","","","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","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","2016-12-30","","","3","","1","","editorialMaterial","","","010301","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","","","" "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","2017-03-06","","","1","","1","","","","","UNSP e25329","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","2017-04-10","","","2","","2","","","","","","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","","","" "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","2017-04-30","","","6","","2","","","","","","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","","","" "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","2017-05-08","http://liu.diva-portal.org/smash/get/diva2:1089940/FULLTEXT01.pdf","","5","","1","","","","","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","2017-05-08","http://liu.diva-portal.org/smash/get/diva2:1089979/FULLTEXT01.pdf","","4","","2","","","","","115130","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","","","" "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-Joesaar, M. P. [n/a] (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","2017-06-19","","","12","","2","","","","","","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","","","" "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","","","" "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","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","2016-08-31","","","10","","2","urn:nbn:se:liu:diva-125919","","","","","true","","","" "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","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","2016-08-31","","","5","","2","","","","","","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","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","2016-08-22","","","2","","2","urn:nbn:se:liu:diva-129564","","","","","false","","","" "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","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","2016-05-12","","","2","","1","","","","","105801","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","","","" "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","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","2016-09-07","","","6","","1","","","","","","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","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","2016-08-22","","","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","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","2016-08-22","","","1","","1","","","","","","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","","","" "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","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","2016-04-20","","","1","","1","","","","","","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","2016-07-11","http://liu.diva-portal.org/smash/get/diva2:936024/FULLTEXT01.pdf","","6","","0","","","","","","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","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","2016-06-13","","","1","","1","","","","","","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","","","" "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","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","2016-09-30","","","8","","2","","","","","","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","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","2016-10-03","","","2","","1","","","","","074501","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","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","2016-10-13","","","11","","2","","","","","","false","","","" "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] (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","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","2016-10-13","","","3","","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","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","2016-10-18","","","20","","1","","","","","","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","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","2016-10-18","","Vetenskapsrådet [621-2011-4249,]","4","","2","","","","","135502","true","","","" "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","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","2016-11-07","http://liu.diva-portal.org/smash/get/diva2:952674/FULLTEXT01.pdf","","6","","1","urn:nbn:se:liu:diva-132272","","","","","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","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","2016-11-07","http://liu.diva-portal.org/smash/get/diva2:1034870/FULLTEXT01.pdf","","5","","2","","","","","085206","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","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","2016-11-07","http://liu.diva-portal.org/smash/get/diva2:1034924/FULLTEXT01.pdf","","5","","2","","","","","","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","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","2016-11-13","","","1","","1","","","","","","true","","","" "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] (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","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","2016-11-13","","","10","","1","","","","","","false","","","" "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","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","2016-11-14","","","2","","1","","","","","104005","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","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","2016-11-15","http://liu.diva-portal.org/smash/get/diva2:1040091/FULLTEXT01.pdf","","6","","2","","","","","","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","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","2016-11-20","","","4","","1","","","","","","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","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","2016-11-21","","","5","","1","","","","","","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","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","2016-12-06","","","3","","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","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","2016-12-08","http://liu.diva-portal.org/smash/get/diva2:1048328/FULLTEXT01.pdf","","4","","2","","","","","","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","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","2016-11-11","http://liu.diva-portal.org/smash/get/diva2:1038466/FULLTEXT01.pdf","","7","","2","","","","","","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","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","2016-12-14","","","10","","2","","","","","","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","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","2016-12-29","http://liu.diva-portal.org/smash/get/diva2:1054734/FULLTEXT01.pdf","","8","","2","","","","","205502","false","","","" "1054743","Caffrey, Nuala M. [n/a] (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","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","2016-12-29","http://liu.diva-portal.org/smash/get/diva2:1054743/FULLTEXT01.pdf","","4","","2","","","","","205411","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","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","2017-01-06","","","5","","1","","","","","","false","","","" "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","","","" "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","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","2017-01-13","","","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","2017-01-22","http://liu.diva-portal.org/smash/get/diva2:1060075/FULLTEXT01.pdf","","9","","2","","","","","220503","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","2017-01-29","http://liu.diva-portal.org/smash/get/diva2:1063078/FULLTEXT01.pdf","","2","","2","","","","","155143","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","","","" "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","2016-07-13","http://liu.diva-portal.org/smash/get/diva2:940230/FULLTEXT01.pdf","","16","","0","","","","","","false","","","" "938938","Olovsson, Weine [n/a] (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","2016-11-28","http://liu.diva-portal.org/smash/get/diva2:938938/FULLTEXT01.pdf","","3","","1","","","","","","true","","","" "934961","Tomita, Kota (University of Tokyo, Japan);Miyata, Tomohiro (University of Tokyo, Japan);Olovsson, Weine [n/a] (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","2016-06-27","","","4","","1","","","","","","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. [n/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","2017-02-15","","","5","","2","","","","","225102","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","","","" "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","2017-03-23","","","8","","1","","","","","","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","","","" "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","2017-04-28","http://liu.diva-portal.org/smash/get/diva2:950633/FULLTEXT01.pdf","","2","","1","","","","","","false","","","" "866364","Ektarawong, Annop [annek02] (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","2017-05-16","","","7","","1","urn:nbn:se:liu:diva-122426;urn:nbn:se:liu:diva-136813","","","","134503","true","","","" "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","2017-05-19","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","2017-05-31","http://liu.diva-portal.org/smash/get/diva2:940490/FULLTEXT01.pdf","","7","","2","","","","","","false","","","" "899814","Dahlqvist, Martin [marda09] (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","2017-05-31","http://liu.diva-portal.org/smash/get/diva2:899814/FULLTEXT01.pdf","","12","","2","","","","","","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","2017-05-31","","","6","","2","urn:nbn:se:liu:diva-122949","","","","104305","true","","","" "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","2017-05-31","http://liu.diva-portal.org/smash/get/diva2:899805/FULLTEXT01.pdf","","6","","2","","","","","","false","","","" "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","","","" "974421","Ektarawong, Annop [annek02] (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","2017-05-16","http://liu.diva-portal.org/smash/get/diva2:974421/FULLTEXT01.pdf","","3","","0","urn:nbn:se:liu:diva-136813","","","","054104","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","","" "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","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","2016-08-31","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","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","2016-08-31","http://liu.diva-portal.org/smash/get/diva2:791634/FULLTEXT01.pdf","","10","","2","","","","","","false","","","" "788717","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])","Core-level spectra from graphene","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","published","91","4","","045402","","2015","","","","American Physical Society","","","","","","10.1103/PhysRevB.91.045402","000347921700007","","","urn:nbn:se:liu:diva-114240","","","","Fysik (103)","","","","<p>We calculate core-level spectra for pristine and doped free-standing graphene sheets. Instructions for how to perform the calculations are given in detail. Although pristine graphene is not metallic the core-level spectrum presents low-energy tailing which is characteristic of metallic systems. The peak shapes vary with doping level in a characteristic way. The spectra are compared to experiments and show good agreement. We compare to two different pristine samples and to one doped sample. The pristine samples are one with quasi-free-standing epitaxial graphene on SiC obtained by hydrogen intercalation and one with a suspended graphene sheet. The doped sample is a gold supported graphene sheet. The gold substrate acts as an acceptor so the graphene sheet gets p doped.</p>","","","","","","","","","","","","","2015-02-16","2015-02-16","2015-02-25","http://liu.diva-portal.org/smash/get/diva2:788717/FULLTEXT01.pdf","","1","","2","","","","","","false","","","" "807076","Jason, Peter [petja31] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Johansson, Magnus [magjo23] [0000-0001-6708-1560] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751])","Charge flipping vortices in the discrete nonlinear Schrodinger trimer and hexamer","Artikel i tidskrift","Refereegranskat","eng","Physical Review E. Statistical, Nonlinear, and Soft Matter Physics","1539-3755","published","91","2","","022910","","2015","","","","American Physical Society","","","","","","10.1103/PhysRevE.91.022910","000351205700005","","","urn:nbn:se:liu:diva-117256","","","","Fysik (103)","","","<p>Funding Agencies|Swedish Research Council</p>","<p>We examine the existence and properties of charge flipping vortices (CFVs), vortices which periodically flip the topological charge, in three-site (trimer) and six-site (hexamer) discrete nonlinear Schrodinger lattices. We demonstrate numerically that CFVs exist as exact quasiperiodic solutions in continuous families which connect two different stationary solutions without topological charge, and that it is possible to interpret the dynamics of certain CFVs as the result of perturbations of these stationary solutions. The CFVs are calculated with high numerical accuracy and we may therefore accurately determine many of their properties, such as their energy and linear stability, and the CFVs are found to be stable over large parameter regimes. We also show that, like in earlier studies for lattices with a multiple of four sites, trimer and hexamer CFVs can be obtained by perturbing stationary constant amplitude vortices with certain linear eigenmodes. However, in contrast to the former case where the perturbation could be infinitesimal, the magnitude of the perturbations for trimers and hexamers must overcome a quite large threshold value. These CFVs may be interpreted as exact quasiperiodic CFVs, with a small perturbation applied. The concept of a charge flipping energy barrier is introduced and discussed.</p>","","","","","","","","","","","","","2015-04-21","2015-04-22","2016-08-22","http://liu.diva-portal.org/smash/get/diva2:807076/FULLTEXT01.pdf","","2","","1","urn:nbn:se:liu:diva-129564","","","","","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","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","2015-10-27","http://liu.diva-portal.org/smash/get/diva2:859362/FULLTEXT01.pdf","","2","","1","","","","","","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","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","2016-03-01","http://liu.diva-portal.org/smash/get/diva2:875198/FULLTEXT01.pdf","","7","","2","urn:nbn:se:liu:diva-122949","","","","","true","","","" "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","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","2015-11-04","http://liu.diva-portal.org/smash/get/diva2:860767/FULLTEXT01.pdf","","3","","1","","","","","","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","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","2015-11-17","http://liu.diva-portal.org/smash/get/diva2:864315/FULLTEXT01.pdf","","3","","2","","","","","","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","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","2016-01-19","http://liu.diva-portal.org/smash/get/diva2:877390/FULLTEXT01.pdf","","2","","1","","","","","104503","false","","","" "811273","Lü, Bo [bolu45] [0000-0002-0908-7187] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanodesign [16854]) (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]);Sarakinos, Kostas [kossa66] [0000-0003-2864-9509] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanodesign [16854]) (Linköpings universitet [276], Tekniska fakulteten [872902])","Coalescence-controlled and coalescence-free growth regimes during deposition of pulsed metal vapor fluxes on insulating surfaces","Artikel i tidskrift","Refereegranskat","eng","Journal of Applied Physics","0021-8979","published","117","13","","","","2015","","","","American Institute of Physics (AIP)","","","","","","10.1063/1.49169831","000352645100033","","","urn:nbn:se:liu:diva-117792","","","","Bearbetnings-, yt- och fogningsteknik (20505)","","","<p>Funding Agencies|Linkoping University via the ""LiU Research Fellows"" program; Swedish Research Council [VR 621-2011-5312]; AForsk through the project ""Towards Next Generation Energy Saving Windows""</p>","<p>The morphology and physical properties of thin films deposited by vapor condensation on solid surfaces are predominantly set by the processes of island nucleation, growth, and coalescence. When deposition is performed using pulsed vapor fluxes, three distinct nucleation regimes are known to exist depending on the temporal profile of the flux. These regimes can be accessed by tuning deposition conditions; however, their effect on film microstructure becomes marginal when coalescence sets in and erases morphological features obtained during nucleation. By preventing coalescence from being completed, these nucleation regimes can be used to control microstructure evolution and thus access a larger palette of film morphological features. Recently, we derived the quantitative criterion to stop coalescence during continuous metal vapor flux deposition on insulating surfaceswhich typically yields 3-dimensional growthby describing analytically the competition between island growth by atomic incorporation and the coalescence rate of islands [Lu et al., Appl. Phys. Lett. 105, 163107 (2014)]. Here, we develop the analytical framework for entering a coalescence-free growth regime for metal vapor deposition on insulating substrates using pulsed vapor fluxes, showing that there exist three distinct criteria for suppressing coalescence that correspond to the three nucleation regimes of pulsed vapor flux deposition. The theoretical framework developed herein is substantiated by kinetic Monte Carlo growth simulations. Our findings highlight the possibility of using atomistic nucleation theory for pulsed vapor deposition to control morphology of thin films beyond the point of island density saturation. (C) 2015 AIP Publishing LLC.</p>","","","","","","","","","","","","","2015-05-08","2015-05-11","2015-05-25","","","3","","2","","","","","134304","false","","","" "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","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","2016-05-12","http://liu.diva-portal.org/smash/get/diva2:811680/FULLTEXT01.pdf","","1","","1","","","","","","true","","","" "813141","Tasnadi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska fakulteten [872902]);Wang, Fei (University of Saarland, 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]) (NUST MISIS, Russia; Tomsk State University, Russia)","Special quasirandom structure method in application for advanced properties of alloys: A study on Ti0.5Al0.5N and TiN/Ti0.5Al0.5N multilayer","Artikel i tidskrift","Refereegranskat","eng","Computational materials science","0927-0256","published","103","","","194","199","2015","","","","Elsevier","","","","","","10.1016/j.commatsci.2015.03.030","000353377100024","","","urn:nbn:se:liu:diva-118022","","","Modelling alloys; Special quasirandom structure approach; Elastic constants; Vacancy formation energy; Multilayers","Fysik (103)","","","<p>Funding Agencies|SSF project Designed Multicomponent coatings, MultiFilms; Erasmus Mundus Programme of the European Commission within the Doctoral Programme DocMASE; Grant of Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Tomsk State University Academic D.I. Mendeleev Fund Program; Swedish Research Council (VR)</p>","<p>The special quasirandom structure (SQS) approach is a successful technique for modelling of alloys, however it breaks inherently the point symmetry of the underlying crystal lattice. We demonstrate that monocrystalline and polycrystalline elastic moduli can scatter significantly depending on the chosen SQS model and even on the supercell orientation in space. Also, we demonstrate that local disturbances, such as vacancies or interfaces change the SQS configuration in a way, that significantly affects the values of the calculated physical properties. Moreover, the diversity of local environments in random alloys results in a large variation of the calculated local properties. We underline that improperly chosen, generated or handled SQS may result in erroneous theoretical findings. The challenges of the SQS method are discussed using bulk Ti0.5Al0.5N alloy and TiN/Ti0.5Al0.5N multilayer as model systems. We present methodological corrections for the mindful application of this approach in studies of advanced properties of alloys.</p>","","","","","","","","","","","","","2015-05-20","2015-05-21","2015-05-28","","","4","","1","","","","","","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","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","2015-06-26","","","4","","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","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","2015-06-30","http://liu.diva-portal.org/smash/get/diva2:827274/FULLTEXT01.pdf","","5","","2","","","","","","false","","","" "843039","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);Münger, Peter [petmu26] (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)","Morphology transition mechanism from icosahedral to decahedral phase during growth of Cu nanoclusters","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","published","92","2","","020102","","2015","","","","American Physical Society","","","","","","10.1103/PhysRevB.92.020102","000357485400001","","","urn:nbn:se:liu:diva-120270","","","","Fysik (103)","","","<p>Funding Agencies|Knut and Alice Wallenberg Foundation [2012.0083]; Swedish Foundation for Strategic Research (SSF) program SRL Grant [10-0026]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]</p>","<p>The morphology transition from the thermodynamically favorable to the unfavorable phase during growth of freestanding copper nanoclusters is studied by molecular dynamics simulations. We give a detailed description of the kinetics and thermodynamics of the process. A universal mechanism of a solid-solid transition, from icosahedral to decahedral morphology in the nanoclusters, is proposed. We show that a formation of distorted NC during the growth process with islands of incoming atoms localized in certain parts of the grown particle may shift the energy balance between Ih and Dh phases in favor of the latter leading to the morphology transition deep within the thermodynamic stability field of the former. The role of diffusion in the morphology transition is revealed. In particular, it is shown that fast diffusion should suppress the morphology transition and favor homogeneous growth of the nanoclusters.</p>","","","","","","","","","","","","","2015-07-24","2015-07-24","2015-08-04","http://liu.diva-portal.org/smash/get/diva2:843039/FULLTEXT01.pdf","","3","","2","","","","","","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","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","2015-08-04","http://liu.diva-portal.org/smash/get/diva2:842655/FULLTEXT01.pdf","","4","","2","","","","","","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","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","2015-08-26","","","8","","1","","","","","","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","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","2015-09-02","http://liu.diva-portal.org/smash/get/diva2:843005/FULLTEXT01.pdf","","2","","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","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","2015-11-30","http://liu.diva-portal.org/smash/get/diva2:841488/FULLTEXT01.pdf","","5","","2","urn:nbn:se:liu:diva-122949","","","","214112","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","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","2016-02-09","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","","" "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","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","2015-12-22","","","1","","1","","editorialMaterial","","","","false","","","" "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","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","2016-08-31","http://liu.diva-portal.org/smash/get/diva2:892924/FULLTEXT01.pdf","","6","","2","urn:nbn:se:liu:diva-125919","","","","","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","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","2016-02-18","http://liu.diva-portal.org/smash/get/diva2:892921/FULLTEXT01.pdf","","3","","2","","","","","","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","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","2016-02-18","http://liu.diva-portal.org/smash/get/diva2:892928/FULLTEXT01.pdf","","7","","1","","","","","","false","","","" "691888","Žukauskaitė, Agnė [agnzu70] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]) (Fraunhofer Institute for Applied Solid State Physics, Freiburg, Germany);Tholander, Christopher [chrth86] [0000-0001-6914-9354] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]);Tasnádi, Ferenc [ferta55] (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]);Pališaitis, Justinas [juspa01] [0000-0003-3203-7935] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]);Lu, Jun [junlu07] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]);Persson, Per O. Å. [perpe25] [0000-0001-9140-6724] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (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]);Birch, Jens [jenbi91] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751])","Stabilization of Wurtzite Sc_0.4Al_0.6N in Pseudomorphic Epitaxial Sc_xAl_1-xN/In_yAl_1-yN Superlattices","Artikel i tidskrift","Refereegranskat","eng","Acta Materialia","1359-6454","published","94","","","101","110","2015","","","","Elsevier","","","","","","10.1016/j.actamat.2015.04.033","000357143500010","","","urn:nbn:se:liu:diva-103831","","","","Naturvetenskap (1)","","","","<p>Pseudomorphic stabilization in wurtzite Sc_xAl_1-xN/AlN and Sc_xAl_1-xN/In_yAl_1-yN superlattices (x=0.2, 0.3, and 0.4; y=0.2-0.72), grown by reactive magnetron sputter epitaxy was investigated. X-ray diffraction and transmission electron microscopy show that in Sc_xAl_1-xN/AlN superlattices the compressive biaxial stresses due to positive lattice mismatch in Sc_0.3Al_0.7N and Sc_0.4Al_0.6N lead to loss of epitaxy, although the structure remains layered. For the negative lattice mismatched In-rich Sc_xAl_1-xN/In_yAl_1-yN superlattices a tensile biaxial stress promotes the stabilization of wurtzite Sc_xAl_1-xN even for the highest investigated concentration x=0.4. Ab initio calculations with fixed in-plane lattice parameters show a reduction in mixing energy for wurtzite Sc_xAl_1-xN under tensile stress when x≥0.375 and support the experimental results.</p>","","","","","","","","","","","","","2014-01-29","2014-01-29","2016-08-31","http://liu.diva-portal.org/smash/get/diva2:691888/FULLTEXT01.pdf","","9","","2","urn:nbn:se:liu:diva-103832;urn:nbn:se:liu:diva-125919","","","","","true","","","" "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","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","2015-03-10","http://liu.diva-portal.org/smash/get/diva2:794102/FULLTEXT01.pdf","","5","","2","","","","","","false","","","" "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","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","2016-04-28","","","6","","1","urn:nbn:se:liu:diva-127496","","","","","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","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","2015-04-21","http://liu.diva-portal.org/smash/get/diva2:795358/FULLTEXT01.pdf","","11","","1","urn:nbn:se:liu:diva-115405","","","","094302","true","","","" "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","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","2016-08-23","http://liu.diva-portal.org/smash/get/diva2:802610/FULLTEXT01.pdf","","4","","2","urn:nbn:se:liu:diva-130517","","","","","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","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","2015-04-21","http://liu.diva-portal.org/smash/get/diva2:802619/FULLTEXT01.pdf","","6","","2","","","","","","false","","","" "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","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","2015-06-03","http://liu.diva-portal.org/smash/get/diva2:802576/FULLTEXT01.pdf","","7","","1","","","","","","false","","","" "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","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","2015-04-21","http://liu.diva-portal.org/smash/get/diva2:802654/FULLTEXT01.pdf","","3","","2","","","","","","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","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","2015-10-06","","","15","","2","","","","","","false","","","" "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","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","2016-10-11","http://liu.diva-portal.org/smash/get/diva2:860769/FULLTEXT01.pdf","","9","","2","urn:nbn:se:liu:diva-131853","","","","","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","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","2016-10-11","http://liu.diva-portal.org/smash/get/diva2:841482/FULLTEXT01.pdf","","8","","2","urn:nbn:se:liu:diva-131853","","","","","false","","","" "784567","Fashandi, Hossein [hosfa18] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tillämpad sensorvetenskap [11901]) (Linköpings universitet [276], Tekniska högskolan [1751]);Ivády, Viktor [vikiv58] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]) (Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest, Hungary);Eklund, Per [perek02] [0000-0003-1785-0864] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]);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]);Katsnelson, Mikhail I. (Radboud University of Nijmegen, Institute for Molecules and Materials, Nijmegen, The Netherlands / Dept. of Theoretical Physics and Applied Mathematics, Ural Federal University, Russia);Abrikosov, Igor A. [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]) (School of Information and Communication Technology, KTH, Stockholm, Sweden)","Dirac points with giant spin-orbit splitting in the electronic structure of two-dimensional transition-metal carbides","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","published","92","15","","","","2015","","","","","","","","","","10.1103/PhysRevB.92.155142","000363512700002","","","urn:nbn:se:liu:diva-113761","","","Cone-point;MAX phase;MXene;Dirac fermion;Spin-orbit coupling","Fysik (103)","","","","<p>We investigated the structural and electrical properties of 2D MXene sheets by means of firstprinciples density functional theory (DFT) calculations. To describe the Kohn-Sham states, plane wave basis set and projector augmented wave method (PAW) were used as implemented in the Vienna ab initio Simulation Package (VASP). We applied PBE parameterization of the generalized gradient approximation of the exchange and correlation energy functional to account for many-body effects of the interacting electron system. Convergent sampling of the Brillouin-zone was achieved by a Γ-centered 15×15×1 grid. In order to model a single sheet of MXene we ensured at least 30 Å vacuum between the periodically repeated sheets. For the structural optimization 1×10−3 eV/Å force criteria was used. The relativistic spin-orbit coupling effects were also included in our simulations regarding band structure and density of states.</p>","","","","","","","","","","","","","2015-01-30","2015-05-01","2016-10-11","http://liu.diva-portal.org/smash/get/diva2:784567/FULLTEXT01.pdf","","6","","2","urn:nbn:se:liu:diva-113763;urn:nbn:se:liu:diva-131474;urn:nbn:se:liu:diva-131853","","","","","true","","","" "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","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","2016-10-11","","","4","","1","","","","","","true","","","" "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","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","2016-10-12","","","3","","1","","","","","","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","2015-09-22","http://liu.diva-portal.org/smash/get/diva2:851813/FULLTEXT01.pdf","","4","","2","","","","","081409","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","","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","2016-08-31","http://liu.diva-portal.org/smash/get/diva2:825126/FULLTEXT01.pdf","","5","","1","","","","","","false","","","" "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; University of Basel, Switzerland; 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","2015-07-31","","","4","","1","","","","","","false","","","" "791447","Vlcek, Vojtech (University of Bayreuth, Germany);Steinle-Neumann, Gerd (University of Bayreuth, Germany);Leppert, Linn (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 högskolan [1751]);Kuemmel, Stephan (University of Bayreuth, Germany)","Improved ground-state electronic structure and optical dielectric constants with a semilocal exchange functional","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","1550-235X","published","91","3","","035107","","2015","","","","American Physical Society","","","","","","","10.1103/PhysRevB.91.035107","000348703700002","","","urn:nbn:se:liu:diva-114585","","","","Fysik (103)","","","<p>Funding Agencies|Deutsche Forschungsgemeinschaft (DFG) [STE1105/8-1, SFB840, B1]; Swedish Research Council [621-2011-4249]; VR</p>","<p>A recently published generalized gradient approximation functional within density functional theory (DFT) has shown, in a few paradigm tests, an improved KS orbital description over standard (semi) local approximations. The characteristic feature of this functional is an enhancement factor that diverges like s ln(s) for large reduced density gradients s which leads to unusual properties. We explore the improved orbital description of this functional more thoroughly by computing the electronic band structure, band gaps, and the optical dielectric constants in semiconductors, Mott insulators, and ionic crystals. Compared to standard semilocal functionals, we observe improvement in both the band gaps and the optical dielectric constants. In particular, the results are similar to those obtained with orbital functionals or by perturbation theory methods in that it opens band gaps in systems described as metallic by standard (semi) local density functionals, e. g., Ge, alpha-Sn, and CdO.</p>","","","","","","","","","","","","","2015-02-26","2015-02-27","2015-03-03","http://liu.diva-portal.org/smash/get/diva2:791447/FULLTEXT01.pdf","","5","","2","","","","","","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","2016-12-09","http://liu.diva-portal.org/smash/get/diva2:812558/FULLTEXT01.pdf","","10","","2","urn:nbn:se:liu:diva-117978","","","","075207","true","","","" "791446","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);Ponomareva, A. V. (NUST MISIS, Russia);Nikonov, A. Yu. (National Research Tomsk State University, Russia; SB RAS, Russia);Zharmukhambetova, A. M. (National Research Tomsk State University, Russia);Mosyagin, Igor [igomo87] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]) (NUST MISIS, Russia);Lugovskoy, A. V. (NUST MISIS, Russia);Hellman, Olle [olohe96] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Lind, Hans [hanli61] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Dmitriev, A. I. (National Research Tomsk State University, Russia; SB RAS, Russia);Barannikova, S. A. (National Research Tomsk State University, Russia; SB RAS, Russia)","Theoretical description of pressure-induced phase transitions: a case study of Ti-V alloys","Artikel i tidskrift","Refereegranskat","eng","High Pressure Research","0895-7959","","published","35","1","","42","48","2015","","","","Taylor andamp; Francis: STM, Behavioural Science and Public Health Titles","","","","","","","10.1080/08957959.2014.992896","000348672100007","","","urn:nbn:se:liu:diva-114586","","","phase stability; first-principles calculations; Ti-V alloys; high pressure","Fysik (103)","","","<p>Funding Agencies|Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; SSF [SRL 10-0026]; Russian Foundation for Basic Researches [13-02-00606a]; Tomsk State University Academic D.I. Mendeleev Fund Program; Program of Fundamental Research of State Academies of Sciences</p>","<p>We discuss theoretical description of pressure-induced phase transitions by means of first-principles calculations in the framework of density functional theory. We illustrate applications of theoretical tools that allow one to take into account configurational and vibrational disorders, considering Ti-V alloys as a model system. The universality of the first-principles theory allows us to apply it in studies of different phenomena that occur in the Ti-V system upon compression. Besides the transitions between different crystal structures, we discuss isostructural transitions in bcc Ti-V alloys. Moreover, we present arguments for possible electronic transitions in this system, which may explain peculiar behaviour of elastic properties of V upon compression.</p>","","","","","","","","","","","","","2015-02-26","2015-02-27","2017-04-10","http://liu.diva-portal.org/smash/get/diva2:791446/FULLTEXT01.pdf","","10","","1","urn:nbn:se:liu:diva-136447","","","","","false","","","" "843894","Ektarawong, Annop [annek02] (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]);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)","Configurational order-disorder induced metal-nonmetal transition in B₁₃C₂ studied with first-principles superatom-special quasirandom structure method","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","1550-235X","published","92","1","","","","2015","","","","American Physical Society","","","","","","","10.1103/PhysRevB.92.014202","000357484100001","","","urn:nbn:se:liu:diva-120344","","","","Fysik (103)","","","<p>Funding Agencies|Swedish Research Council (VR) [621-2011-4417, 330-2014-6336, 2014-4750]; CeNano at Linkoping University; LiLi-NFM; Swedish Government Strategic Research Area Grant in Materials Science</p>","<p>Due to a large discrepancy between theory and experiment, the electronic character of crystalline boron carbide B13C2 has been a controversial topic in the field of icosahedral boron-rich solids. We demonstrate that this discrepancy is removed when configurational disorder is accurately considered in the theoretical calculations. We find that while the ordered ground state B13C2 is metallic, the configurationally disordered B13C2, modeled with a superatom-special quasirandom structure method, goes through a metal to nonmetal transition as the degree of disorder is increased with increasing temperature. Specifically, one of the chain-end carbon atoms in the CBC chains substitutes a neighboring equatorial boron atom in a B-12 icosahedron bonded to it, giving rise to a B11Ce(BBC) unit. The atomic configuration of the substitutionally disordered B13C2 thus tends to be dominated by a mixture between B-12(CBC) and B11Ce(BBC). Due to splitting of valence states in B11Ce(BBC), the electron deficiency in B-12(CBC) is gradually compensated.</p>","","","","","","","","","","","","","2015-07-31","2015-07-31","2017-05-16","http://liu.diva-portal.org/smash/get/diva2:843894/FULLTEXT01.pdf","","5","","2","urn:nbn:se:liu:diva-122426;urn:nbn:se:liu:diva-136813","","","","014202","false","","","" "724315","Li, C.W. ( Oak Ridge National Lab, TN 37831 USA );Hellman, Olle [olohe96] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Ma, J. (Oak Ridge National Lab, TN 37831 USA );May, A.F. (Oak Ridge National Lab, TN 37831 USA );Cao, H.B. (Oak Ridge National Lab, TN 37831 USA );Chen, X. (Oak Ridge National Lab, TN 37831 USA );Christianson, A.D. (Oak Ridge National Lab, TN 37831 USA );Ehlers, G. (Oak Ridge National Lab, TN 37831 USA );Singh, D.J. (Oak Ridge National Lab, TN 37831 USA );Sales, B.C. (Oak Ridge National Lab, TN 37831 USA );Delaire, O. (Oak Ridge National Lab, TN 37831 USA )","Phonon Self-Energy and Origin of Anomalous Neutron Scattering Spectra in SnTe and PbTe Thermoelectrics","Artikel i tidskrift","Refereegranskat","eng","Physical Review Letters","0031-9007","published","112","17","","175501","","2014","","","","American Physical Society","","","","","","10.1103/PhysRevLett.112.175501","000335816700014","","","urn:nbn:se:liu:diva-107454","","","","Teknik och teknologier (2)","","","","<p>The anharmonic lattice dynamics of rock-salt thermoelectric compounds SnTe and PbTe are investigated with inelastic neutron scattering (INS) and first-principles calculations. The experiments show that, surprisingly, although SnTe is closer to the ferroelectric instability, phonon spectra in PbTe exhibit a more anharmonic character. This behavior is reproduced in first-principles calculations of the temperature-dependent phonon self-energy. Our simulations reveal how the nesting of phonon dispersions induces prominent features in the self-energy, which account for the measured INS spectra and their temperature dependence. We establish that the phase space for three-phonon scattering processes, combined with the proximity to the lattice instability, is the mechanism determining the complex spectrum of the transverse-optic ferroelectric mode.</p>","","","","","","","","","","","","","2014-06-12","2014-06-12","2014-06-25","http://liu.diva-portal.org/smash/get/diva2:724315/FULLTEXT01.pdf","","11","","2","","","","","","false","","","" "724312","Ghafoor, Naureen [naugh16] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska högskolan [1751]);Lind, Hans [hanli61] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Tasnadi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (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]);Odén, Magnus [magod41] [0000-0002-2286-5588] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska högskolan [1751])","Anomalous epitaxial stability of (001) interfaces in ZrN/SiNx multilayers","Artikel i tidskrift","Refereegranskat","eng","APL Materials","2166-532X","published","2","4","","046106","","2014","","","","American Institute of Physics","","","","","","10.1063/1.4870876","000336083600007","","","urn:nbn:se:liu:diva-107456","","","","Teknik och teknologier (2)","","","","<p>Isostructural stability of B1-NaCl type SiN on (001) and (111) oriented ZrN surfaces is studied theoretically and experimentally. The ZrN/SiNx/ZrN superlattices with modulation wavelength of 3.76 nm (dSiNx similar to 0.4 nm) were grown by dc-magnetron sputtering on MgO(001) and MgO(111). The results indicate that 0.4 nm thin SiNx layers utterly influence the preferred orientation of epitaxial growth: on MgO(001) cube-on-cube epitaxy of ZrN/SiNx superlattices were realized whereas multilayers on MgO(111) surface exhibited an unexpected 002 texture with a complex fourfold 90 degrees-rotated in-plane preferred orientation. Density functional theory calculations confirm stability of a (001) interface with respect to a (111) which explains the anomaly.</p>","","","","","","","","","","","","","2014-06-12","2014-06-12","2015-03-16","","","5","","0","urn:nbn:se:liu:diva-115405","","","","","true","","","" "732887","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 högskolan [1751])","Large amplitude electron plasma oscillations","Artikel i tidskrift","Refereegranskat","eng","Physics Letters A","0375-9601","published","378","22-23","","1632","1635","2014","","","","Elsevier","","","","","","10.1016/j.physleta.2014.04.011","000336868400008","","","urn:nbn:se:liu:diva-108813","","","Large amplitude waves; Plasma oscillations; Parametric processes","Teknik och teknologier (2)","","","","<p>We consider a cold plasma in order to find new large-amplitude wave solutions in the long-wavelength limit. Accordingly we derive two generic coupled equations which describe the energy exchange between the electrostatic and electromagnetic waves. A new kind of quasi-periodic behavior is found. Our derivations may be considered as a prerequisite to extended studies of stimulated Raman scattering for cases where the wave amplitudes are so large that standard perturbation techniques are not applicable.</p>","","","","","","","","","","","","","2014-07-06","2014-07-07","2014-07-07","","","2","","1","","","","","","false","","","" "725849","Wahlstrand, B (HiQ Mälardalen AB, Arboga, Sweden);Yakymenko, Iryna [iryya88] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Berggren, Karl-Fredrik [karbe79] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751])","Wave transport and statistical properties of an open non-Hermitian quantum dot with parity-time symmetry","Artikel i tidskrift","Refereegranskat","eng","Physical Review E. Statistical, Nonlinear, and Soft Matter Physics","1539-3755","published","89","062910","","","","2014","","","","American Physical Society","","","","","","10.1103/PhysRevE.89.062910","000338019800014","","","urn:nbn:se:liu:diva-107613","","","","Naturvetenskap (1)","","","","<p>A basic quantum-mechanical model for wave functions and current flow in open quantum dots or billiards is investigated. The model involves non-Hertmitian quantum mechanics, parity-time (PT) symmetry, and PT-symmetry breaking. Attached leads are represented by positive and negative imaginary potentials. Thus probability densities, currents flows, etc., for open quantum dots or billiards may be simulated in this way by solving the Schrödinger equation with a complex potential. Here we consider a nominally open ballistic quantum dot emulated by a planar microwave billiard. Results for probability distributions for densities, currents (Poynting vector), and stress tensor components are presented and compared with predictions based on Gaussian random wave theory. The results are also discussed in view of the corresponding measurements for the analogous microwave cavity. The model is of conceptual as well as of practical and educational interest.</p>","","","","","","","","","","","","","2014-06-17","2014-06-17","2014-08-13","http://liu.diva-portal.org/smash/get/diva2:725849/FULLTEXT01.pdf","","3","","1","","","","","","true","","","" "727882","Falk, Abram L. ( University of Chicago, IL 60637 USA University of Calif Santa Barbara, CA 93106 USA );Klimov, Paul V. (University of Chicago, IL 60637 USA University of Calif Santa Barbara, CA 93106 USA );Buckley, Bob B. (University of Calif Santa Barbara, CA 93106 USA );Ivády, Viktor [vikiv58] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (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]);Calusine, Greg (University of Calif Santa Barbara, CA 93106 USA );Koehl, William F. (University of Chicago, IL 60637 USA University of Calif Santa Barbara, CA 93106 USA );Gali, Adam (Hungarian Academic Science, Hungary Budapest University of Technology and Econ, Hungary );Awschalom, David D. (University of Chicago, IL 60637 USA University of Calif Santa Barbara, CA 93106 USA )","Electrically and Mechanically Tunable Electron Spins in Silicon Carbide Color Centers","Artikel i tidskrift","Refereegranskat","eng","Physical Review Letters","0031-9007","published","112","18","","187601","","2014","","","","American Physical Society","","","","","","10.1103/PhysRevLett.112.187601","000336099800011","","","urn:nbn:se:liu:diva-107840","","","","Teknik och teknologier (2)","","","","<p>The electron spins of semiconductor defects can have complex interactions with their host, particularly in polar materials like SiC where electrical and mechanical variables are intertwined. By combining pulsed spin resonance with ab initio simulations, we show that spin-spin interactions in 4H-SiC neutral divacancies give rise to spin states with a strong Stark effect, sub-10(-6) strain sensitivity, and highly spin-dependent photoluminescence with intensity contrasts of 15%-36%. These results establish SiC color centers as compelling systems for sensing nanoscale electric and strain fields.</p>","","","","","","","","","","","","","2014-06-23","2014-06-23","2014-06-25","http://liu.diva-portal.org/smash/get/diva2:727882/FULLTEXT01.pdf","","9","","2","","","","","","false","","","" "721394","Johansson, Magnus [magjo23] [0000-0001-6708-1560] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Prilepsky, Jaroslaw E. (Aston University, Birmingham, UK);Derevyanko, Stanislav A. (Weizmann Institute Science, Rehovot, Israel )","Strongly localized moving discrete dissipative breather-solitons in Kerr nonlinear media supported by intrinsic gain","Artikel i tidskrift","Refereegranskat","eng","Physical Review E. Statistical, Nonlinear, and Soft Matter Physics","1539-3755","published","89","4","","042912-1","042912-9","2014","","","","American Physical Society","","","","","","10.1103/PhysRevE.89.042912","000335239200009","","","urn:nbn:se:liu:diva-106961","","","","Teknik och teknologier (2)","","","","<p>We investigate the mobility of nonlinear localized modes in a generalized discrete Ginzburg-Landau-type model, describing a one-dimensional waveguide array in an active Kerr medium with intrinsic, saturable gain and damping. It is shown that exponentially localized, traveling discrete dissipative breather-solitons may exist as stable attractors supported only by intrinsic properties of the medium, i.e., in the absence of any external field or symmetry-breaking perturbations. Through an interplay by the gain and damping effects, the moving soliton may overcome the Peierls-Nabarro barrier, present in the corresponding conservative system, by self-induced time-periodic oscillations of its power (norm) and energy (Hamiltonian), yielding exponential decays to zero with different rates in the forward and backward directions. In certain parameter windows, bistability appears between fast modes with small oscillations and slower, large-oscillation modes. The velocities and the oscillation periods are typically related by lattice commensurability and exhibit period-doubling bifurcations to chaotically walking modes under parameter variations. If the model is augmented by intersite Kerr nonlinearity, thereby reducing the Peierls-Nabarro barrier of the conservative system, the existence regime formoving solitons increases considerably, and a richer scenario appears including Hopf bifurcations to incommensurately moving solutions and phase-locking intervals. Stable moving breathers also survive in the presence of weak disorder.</p>","","","","","","","","","","","","","2014-06-02","2014-06-04","2014-06-12","http://liu.diva-portal.org/smash/get/diva2:721394/FULLTEXT01.pdf","","3","","1","","","","","","true","","","" "738022","Thiyam, P. (Royal Institute of Technology, Stockholm, Sweden);Boström, M. (Royal Institute of Technology, Stockholm, Sweden; University of Oslo, Norway; Norwegian University of Science and Technology, Trondheim, Norway );Persson, C. (Royal Institute of Technology, Stockholm, Sweden; University of Oslo, Norway );Parsons, D. F. (Australian National University, Australia );Brevik, I. (Norwegian University of Science and Technology,Trondheim, 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])","Finite-size-dependent dispersion potentials between atoms and ions dissolved in water","Artikel i tidskrift","Refereegranskat","eng","Europhysics letters","0295-5075","published","106","5","","53002","","2014","","","","European Physical Society","","","","","","10.1209/0295-5075/106/53002","000339151800008","","","urn:nbn:se:liu:diva-109396","","","","Fysik (103)","","","","<p>A non-expanded theory is used for dispersion potentials between atoms and ions dissolved in a medium. The first-order dispersion interaction between two atoms in an excited state must account for the fact that the two atoms are coupled via the electromagnetic field and must include effects from background media, retardation and finite size. We show that finite-size corrections when two particles are close change the dispersion interactions in water by several orders of magnitude. We consider as four illustrative examples helium atoms, krypton atoms, phosphate ions, and iodide ions. We demonstrate that, due to large cancellation effects, retardation dominates the interaction for helium atom pairs in an isotropic excited state down to the very small atom-atom separations where finite-size corrections are also important.</p>","","","","","","","","","","","","","2014-08-15","2014-08-15","2014-09-18","http://liu.diva-portal.org/smash/get/diva2:738022/FULLTEXT01.pdf","","6","","1","","","","","","true","","","" "748737","Ingason, Arni Sigurdur [arnin42] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]);Petruhins, Andrejs [andpe38] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]);Dahlqvist, Martin [marda09] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]);Magnus, F. (Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden/Science Institute, University of Iceland, Iceland);Mockuté, Aurelija [aurmo58] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (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]);Lu, Jun [junlu07] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (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 A. [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Persson, Per O Å [perpe25] [0000-0001-9140-6724] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]);Rosén, Johanna [johro07] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751])","A Nanolaminated Magnetic Phase: Mn₂GaC","Artikel i tidskrift","Refereegranskat","eng","Research Letters in Materials Science","1687-6822","published","2","2","","89","93","2014","","","","Taylor & Francis","","","","","","10.1080/21663831.2013.865105","","","","urn:nbn:se:liu:diva-110763","","","MAX Phases;Magnetism;Thin Films;First Principles Calculations;Phase Stability","Fysik (103)","","","","<p>We report on first principles prediction and subsequent synthesis of Mn₂GaC, a new member of the inherently nanolaminated <em>M</em>_<em>n</em>+1<em>AX</em>_<em>n</em> (MAX) phase family. This phase, the first to include Mn as the sole <em>M</em> element, was synthesized as a heteroepitaxial thin film. The material was theoretically predicted to display magnetic ordering with ferromagnetic (FM) and antiferromagnetic configurations degenerate in energy within the computational accuracy. Vibrating sample magnetometer measurements show FM ordering with a saturation moment of <em>m</em>_s=0.29 μB per Mn atom and remanent moment of <em>m</em>_r=0.15 μB per Mn atom for temperatures≤230 K.</p>","","","","","","","","","","","","","2014-09-22","2014-09-22","2016-08-31","","","11","","1","urn:nbn:se:liu:diva-110764","","","","","true","","","" "741436","Ritchie, Andrew (University of Saskatchewan, Saskatoon, SK, Canada);Eger, Shaylin (University of Saskatchewan, Saskatoon, SK, Canada);Wright, Chelsey (Canadian Light Source, Saskatoon, SK, Canada);Chelladurai, Saniel (University of Saskatchewan, Saskatoon, SK, Canada);Borrowman, Cuyler (University of Saskatchewan, Saskatoon, SK, Canada);Olovsson, Weine [weiol14] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Magnuson, Martin [marma66] [0000-0002-0317-0190] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]);Verma, Jai (University of Notre Dame, IN, USA);Jena, Debdeep (Univeristy of Notre Dame, IN, USA);Grace Xing, Huili (University of Notre Dame, IN, USA);Duboc, Christian (Osemi Canada Inc., Sherbrooke, Quebec, Canada);Urquhart, Stephen (University of Saskatchewan, Saskatoon, SK, Canada)","Strain sensitivity in the nitrogen 1s NEXAFS spectra of gallium nitride","Artikel i tidskrift","Refereegranskat","eng","Applied Surface Science","0169-4332","published","316","","","232","236","2014","","","","Elsevier","","","","https://people.ifm.liu.se/marma/;http://arxiv.org/ftp/arxiv/papers/1408/1408.6921.pdf","","10.1016/j.apsusc.2014.07.070","000343329100034","","","urn:nbn:se:liu:diva-109795","","","GaN;Semiconductor strain;NEXAFS;XANES","Fysik (103)","","","","<p>The nitrogen 1s near edge X-ray absorption fine structure (NEXAFS) of gallium nitride (GaN) shows astrong natural linear dichroism that arises from its anisotropic wurtzite structure. An additional spectro-scopic variation arises from lattice strain in epitaxially grown GaN thin films. This variation is directlyproportional to the degree of strain for some spectroscopic features. This strain variation is interpretedwith the aid of density functional theory calculations.</p>","","","","","","","","","","","","","2014-08-28","2014-08-28","2014-11-24","http://liu.diva-portal.org/smash/get/diva2:741436/FULLTEXT02.pdf","","12","","1","","","","","","true","","","" "737206","Sangiovanni, Davide [davsa82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Edström, Daniel [daned22] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (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]);Petrov, Ivan [ivape26] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]) (University of Illinois, Urbana, 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, Urbana, USA);Chirita, Valeriu [valch35] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751])","Ti adatom diffusion on TiN(001) : Ab initio and classical molecular dynamics simulations","Artikel i tidskrift","Refereegranskat","eng","Surface Science","0039-6028","published","627","","","34","41","2014","","","","Elsevier","","","","","","10.1016/j.susc.2014.04.007","000338621500006","","","urn:nbn:se:liu:diva-109215","","","Surface diffusion; Nitrides; Molecular dynamics simulations; Density functional theory","Fysik (103)","","","","<p>Ab initio and classical molecular dynamics (AIMD and CMD) simulations reveal that Ti adatoms on TiN(001) surfaces migrate between neighboring fourfold hollow sites primarily along in-plane less than100greater than channels. less than100greater than and less than110greater than single jumps, as well as less than100greater than double jump rates, obtained directly from MD runs as a function of temperature, are used to determine diffusion activation energies Ea, and attempt frequencies A, for the three preferred Ti adatom migration pathways on TiN(001). From transition rates Aexp[-Ea / (k(B)T)], we determine adatom surface distribution probabilities as a function of time, which are used to calculate adatom diffusion coefficients D(T). AIMD and CMD predictions are consistent and complementary. Using CMD, we investigate the effect on the adatom jump rate of varying the phonon wavelength degrees of freedom by progressively increasing the supercell size. We find that long-wavelength phonons significantly contribute to increasing adatom mobilities at temperatures less than= 600 K, but not at higher temperatures. Finally, by directly tracking the Ti adatom mean-square displacement during CMD runs, we find that Ti adatom jumps are highly correlated on TiN(001), an effect that yields lower D-s values (D-s(corr)) than those estimated from uncorrelated transition probabilities. The temperature-dependent diffusion coefficient is D-s(corr) (T) = (4.5 x 10(-4) Cm-2 s(-1)) exp[-0.55 eV / (k(B)T)].</p>","","","","","","","","","","","","","2014-08-11","2014-08-12","2016-08-31","http://liu.diva-portal.org/smash/get/diva2:737206/FULLTEXT01.pdf","","6","","1","","","","","","true","","","" "746897","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 högskolan [1751])","Wave Generation in a Warm Magnetized Multi-Component Plasma","Artikel i tidskrift","Refereegranskat","eng","Contributions to Plasma Physics","0863-1042","published","54","7","","623","625","2014","","","","Wiley-VCH Verlag","","","","","","10.1002/ctpp.201300054","000340499400001","","","urn:nbn:se:liu:diva-110484","","","Parametric instabilities; THz radiation","Fysik (103)","","","","<p>The resonant interaction between three waves propagating perpendicularly to an external magnetic field in a plasma is considered. We present the explicit expressions for the three wave coupling coefficients of a warm multi-component plasma. The results of previous work on the generation of THz radiation by laser plasma interaction are significantly improved.</p>","","","","","","","","","","","","","2014-09-12","2014-09-15","2014-09-15","","","2","","1","","","","","","false","","","" "744520","Tholander, Christopher [chrth86] [0000-0001-6914-9354] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (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]);Tasnádi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Greene, Joseph E. [josgr17] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (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])","Effect of Al substitution on Ti, Al, and N adatom dynamics on TiN(001), (011), and (111) surfaces","Artikel i tidskrift","Refereegranskat","eng","Surface Science","0039-6028","published","630","","","28","40","2014","","","","Elsevier","","","","","","10.1016/j.susc.2014.06.010","000344435900005","","","urn:nbn:se:liu:diva-110351","","","Diffusion;First principles;Surface diffusion;TiAlN;Titanium nitrides","Den kondenserade materiens fysik (10304)","","","","<p>Substituting Al for Ti in TiN(001), TiN(011), and N- and Ti-terminated TiN(111) surfaces has significant effects on adatom surface energetics which vary strongly with the adatom species and surface orientation. Here, we investigate Ti, Al, and N adatom surface dynamics using density functional methods. We calculate adatom binding and diffusion energies with both a nudged elastic band and grid-probing techniques. The adatom diffusivities are analyzed within a transition-state theory approximation. We determine the stable and metastable Ti, Al, and N binding sites on all three surfaces as well as the lowest energy migration paths. In general, adatom mobilities are fastest on TiN(001), slower on TiN(111), and slowest on TiN(011). The introduction of Al has two major effects on the surface diffusivity of Ti and Al adatoms. First, Ti adatom diffusivity on TiN(001) is significantly reduced near substituted Al surface atoms; we observe a 200% increase in Ti adatom diffusion barriers out of fourfold hollow sites adjacent to Al surface atoms, while Al adatom diffusivity between bulk sites is largely unaffected. Secondly, on TiN(111), the effect is opposite; Al adatoms are slowed near the substituted Al surface atom, while Ti adatom diffusivity is largely unaffected. In addition, we note the importance of magnetic spin polarization on Ti adatom binding energies and diffusion path. These results are of relevance for the atomistic understanding of Ti_1-xAl_xN alloy and Ti_1-xAl_xN/TiN multilayer thin-film growth processes.</p>","","","","","","","","","","","","","2014-09-08","2014-09-08","2016-08-31","http://liu.diva-portal.org/smash/get/diva2:744520/FULLTEXT02.pdf","","5","","1","urn:nbn:se:liu:diva-110363;urn:nbn:se:liu:diva-125919","","","","","true","","","" "748114","Lind, Hans [hanli61] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Pilemalm, Robert [robpi36] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska högskolan [1751]);Rogström, Lina [linro82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska högskolan [1751]);Tasnadi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Ghafoor, Naureen [naugh16] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska högskolan [1751]);Forsén, Rikard [rikfo25] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska högskolan [1751]);Johnson, Lars (Sandvik Coromant, Stockholm, Sweden);Jöesaar, Mats [matjo02] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska högskolan [1751]) (SECO Tools AB, Fagersta, 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 högskolan [1751]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751])","High temperature phase decomposition in Ti_xZr_yAl_zN","Artikel i tidskrift","Refereegranskat","eng","AIP Advances","2158-3226","published","4","12","","127147-1","127147-9","2014","","","","American Institute of Physics (AIP)","","","","","","10.1063/1.4905138","000347170100078","","","urn:nbn:se:liu:diva-110682","","","","Fysik (103)","","","<p>On the day of the defence date the status of this article was <em>Manuscript</em>.</p>","<p>Through a combination of theoretical and experimental observations we study the high temperature decomposition behavior of c-(Ti_xZr_yAl_zN) alloys. We show that for most concentrations the high formation energy of (ZrAl)N causes a strong tendency for spinodal decomposition between ZrN and AlN while other decompositions tendencies are suppressed. In addition we observe that entropic  effects due to configurational disorder favor a formation of a stable Zr-rich (TiZr)N phase with increasing temperature. Our calculations also predict that at high temperatures a Zr rich (TiZrAl)N disordered phase should become more resistant against the spinodal decomposition despite its high and positive formation energy due to the specific topology of the free energy surface at the relevant concentrations. Our experimental observations confirm this prediction by showing strong tendency towards decomposition in a Zr-poor sample while a Zr-rich alloy shows a greatly reduced decomposition rate, which is mostly attributable to binodal decomposition processes. This result highlights the importance of considering the second derivative of the free energy, in addition to its absolute value in predicting decomposition trends of thermodynamically unstable alloys.</p>","","","","","","","","","","","","","2014-09-18","2014-09-18","2015-06-01","http://liu.diva-portal.org/smash/get/diva2:748114/FULLTEXT01.pdf","","10","","1","urn:nbn:se:liu:diva-110684;urn:nbn:se:liu:diva-112213;urn:nbn:se:liu:diva-115405","","","","","true","","","" "748108","Forsén, Rikard [rikfo25] (Linköpings universitet [276], Tekniska högskolan [1751]) (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]);Schramm, I. C. (Functional Materials, Department Materials Science, Saarland University, Saarbrücken, Germany);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Persson, Per O Å [perpe25] [0000-0001-9140-6724] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]);Mücklich, F. (Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden-Rossendorf);Odén, Magnus [magod41] [0000-0002-2286-5588] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska högskolan [1751]);Ghafoor, Naureen [naugh16] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska högskolan [1751])","Nanostructuring and coherency strain in multicomponent hard coatings","Artikel i tidskrift","Refereegranskat","eng","APL MATERIALS","2166-532X","published","2","11","","116104","","2014","","","","American Institute of Physics (AIP)","","","","http://scitation.aip.org/","","10.1063/1.4901125","000345638800023","","","urn:nbn:se:liu:diva-110678","","","Age hardening; Spinodal decomposition; Cathodic arc evaporation; Aberration corrected TEM","Fysik (103)","","","","<p>Lattice resolved and quantitative compositional characterizations of the microstructure in TiCrAlN wear resistant coatings emerging at elevated temperatures are performed to address the spinodal decomposition into nanometer-sized coherent cubic TiCr- and Al-rich domains. The domains coarsen during annealing and at 1100 ºC, the Al-rich domains include a metastable cubic Al(Cr)N phase containing 9 at.% Cr and a stable hexagonal AlN phase containing less than 1 at.% Cr. The cubic and the hexagonal phases form strained semi-coherent interfaces with each other.</p>","","","","","","","","","","","","","2014-09-18","2014-09-18","2015-03-09","http://liu.diva-portal.org/smash/get/diva2:748108/FULLTEXT01.pdf","","7","","1","urn:nbn:se:liu:diva-110684","","","","","true","","","" "744024","Ponomareva, A. V. (National University of Science and Technology MISIS, 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 högskolan [1751])","Ab initio calculation of the solution enthalpies of substitutional and interstitial impurities in paramagnetic fcc Fe","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","published","90","1","","014439","","2014","","","","American Physical Society","","","","","","10.1103/PhysRevB.90.014439","000339973900002","","","urn:nbn:se:liu:diva-110288","","","","Fysik (103)","","","<p>Funding Agencies|Russian Federation Ministry for Science and Education [14.Y26.31.0005]; Swedish Foundation for Strategic Research, program Succesful Research Leader [744 10-0026]; Russian Foundation for Basic Researches [13-02-00-606a]</p>","<p>In the framework of disordered local moment approach by using magnetic sampling method, we suggested a model that takes into account the magnetic disorder in paramagnetic Fe with point defects. We calculate solution enthalpies of substitutional (Nb, V) and interstitial (C, N) impurities in paramagnetic face-centered cubic Fe and obtain results that are in agreement with available experimental data. It is found that both interstitial and substitutional atoms may favor the local magnetic polarization of the Fe host around the impurities by decreasing the potential energy of the system. The possibility of a formation of predominantly ferromagnetic Fe clusters around carbon in the temperature range of overcooled austenite is discussed.</p>","","","","","","","","","","","","","2014-09-05","2014-09-05","2014-09-09","http://liu.diva-portal.org/smash/get/diva2:744024/FULLTEXT01.pdf","","3","","2","","","","","","false","","","" "755285","Onishchenko, O. G. (Institute Phys Earth, Russia; Moscow Space Research Institute, Russia);Horton, W. (Institute Mediterranean AMU, France; University of Texas Austin, TX 78712 USA; Aix Marseilles University, France);Pokhotelov, O. A. (Institute Phys Earth, Russia);Stenflo, Lennart [lenst65] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751])","Dust devil generation","Artikel i tidskrift","Refereegranskat","eng","Physica Scripta","0031-8949","published","89","7","","075606","","2014","","","","IOP Publishing: Hybrid Open Access","","","","","","10.1088/0031-8949/89/7/075606","000341561800028","","","urn:nbn:se:liu:diva-111299","","","vortex structures; internal gravity waves; tornadoes; temperature gradients","Fysik (103)","","","<p>Funding Agencies|International Space Science Institute in Bern (Switzerland); Russian Academy of Sciences [8, 22]; RFBR [14-05-00850]; NSF [0964692]; University of Aix-Marseille/CNRS; IMeRA Grant for Advanced Research</p>","<p>The equations describing axi-symmetric nonlinear internal gravity waves in an unstable atmosphere are derived. A hydrodynamic model of a dust devil generation mechanism in such an atmosphere is investigated. It is shown that in an unstably stratified atmosphere the convective plumes with poloidal motion can grow exponentially. Furthermore, it is demonstrated that these convective plumes in an atmosphere with weak large scale toroidal motion are unstable with respect to three-dimensional dust devil generation.</p>","","","","","","","","","","","","","2014-10-14","2014-10-14","2015-01-22","","","4","","1","","","","","","false","","","" "760305","Sangiovanni, Davide [davsa82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Edström, Daniel [daned22] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (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]);Petrov, Ivan [ivape26] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]) (University of Illinois, Urbana, 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, Urbana, USA);Chirita, Valeriu [valch35] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751])","Ab-initio and classical molecular dynamics simulations of N₂ desorption from TiN(001) surfaces","Artikel i tidskrift","Refereegranskat","eng","Surface Science","0039-6028","published","624","","","25","31","2014","","","","Elsevier","","","","","","10.1016/j.susc.2014.01.007","000335097900005","","","urn:nbn:se:liu:diva-111791","","","N2 desorption; Surface diffusion; Nitrides; Molecular dynamics simulations; Density functional theory; Vacancy formation","Fysik (103)","","","","<p><em>Ab initio</em> molecular dynamics simulations based on density functional theory show that N adatoms are chemisorbed in threefold sites close to a N surface atom and between the two diagonally opposed neighboring Ti surface atoms on TiN(001). The most probable N adatom reaction pathway, even in the presence of nearby N adatoms, is for the N adatom and N surface atom pair to first undergo several exchange reactions and then desorb as a N₂ molecule, resulting in a surface anion vacancy, with an activation barrier <em>E</em>_des of 1.37 eV and an attempt frequency <em>A</em>_des = 3.4 × 10¹³ s^− 1. <em>E</em>_des is essentially equal to the N adatom surface diffusion barrier, <em>E_s</em> = 1.39 eV, while <em>A_s</em> is only three to four times larger than <em>A</em>_des, indicating that isolated N adatoms migrate for only short distances prior to N₂ desorption. The probability of N₂ desorption via recombination of N adatoms on TiN(001) is much lower due to repulsive adatom/adatom interactions at separations less than ~ 3 Å which rapidly increase to ~ 2 eV at a separation of 1.5 Å. We obtain good qualitative and quantitative agreement with the above results using the modified embedded atom method potential to perform classical molecular dynamics simulations.</p>","","","","","","","","","","","","","2014-11-03","2014-11-03","2016-08-31","http://liu.diva-portal.org/smash/get/diva2:760305/FULLTEXT01.pdf","","6","","1","","","","","","true","","","" "751584","Shulumba, Nina [ninsh46] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (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]);Hellman, Olle [olohe96] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Mozafari, Elham [elhmo04] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Beräkningsfysik [2208]) (Linköpings universitet [276], Tekniska högskolan [1751]);Steneteg, Peter [petst55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Odén, Magnus [magod41] [0000-0002-2286-5588] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (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])","Vibrational free energy and phase stability of paramagnetic and antiferromagnetic CrN from <em>ab initio</em> molecular dynamics","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","published","89","17","","174108","","2014","","","","American Physical Society","","","","","","10.1103/PhysRevB.89.174108","000341308600001","","","urn:nbn:se:liu:diva-110985","","","","Fysik (103)","","","<p>Funding Agencies|Erasmus Mundus Joint European Doctoral Programme DocMASE; SECO Tools AB; Swedish Research Council [621-2011-4426, 621-2011-4417]; Swedish Foundation for Strategic Research (SSF) programs SRL [10-0026]; project Designed Multicomponent Coatings (MultiFilms); Knut and Alice Wallenberg Foundation (KAW)</p>","<p>We present a theoretical first-principles method to calculate the free energy of a magnetic system in its high-temperature paramagnetic phase, including vibrational, electronic, and magnetic contributions. The method for calculating free energies is based on ab initio molecular dynamics and combines a treatment of disordered magnetism using disordered local moments molecular dynamics with the temperature-dependent effective potential method to obtain the vibrational contribution to the free energy. We illustrate the applicability of the method by obtaining the anharmonic free energy for the paramagnetic cubic and the antiferromagnetic orthorhombic phases of chromium nitride. The influence of lattice dynamics on the transition between the two phases is demonstrated by constructing the temperature-pressure phase diagram.</p>","","","","","","","","","","","","","2014-10-01","2014-10-01","2016-08-23","http://liu.diva-portal.org/smash/get/diva2:751584/FULLTEXT01.pdf","","7","","2","urn:nbn:se:liu:diva-122949;urn:nbn:se:liu:diva-130517","","","","","true","","","" "758550","Thiyam, Priyadarshini (Royal Institute Technology, Sweden);Persson, Clas (Royal Institute Technology, Sweden; University of Oslo, Norway; University of Oslo, 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]);Parsons, Drew F. (Australian National University, Australia);Malthe-Sorenssen, Anders (University of Oslo, Norway);Bostrom, Mathias (Royal Institute Technology, Sweden; University of Oslo, Norway; Norwegian University of Science and Technology, Norway)","Intermolecular Casimir-Polder forces in water and near surfaces","Artikel i tidskrift","Refereegranskat","eng","Physical Review E. Statistical, Nonlinear, and Soft Matter Physics","1539-3755","published","90","3","","032122","","2014","","","","American Physical Society","","","","","","10.1103/PhysRevE.90.032122","000342562600002","","","urn:nbn:se:liu:diva-111604","","","","Fysik (103)","","","<p>Funding Agencies|European Commission; Research Council of Norway [221469]; Swedish Research Council [90499401]; Department of Energy and Process Engineering (NTNU, Norway); Australian Commonwealth Government</p>","<p>The Casimir-Polder force is an important long-range interaction involved in adsorption and desorption of molecules in fluids. We explore Casimir-Polder interactions between methane molecules in water, and between a molecule in water near SiO2 and hexane surfaces. Inclusion of the finite molecular size in the expression for the Casimir-Polder energy leads to estimates of the dispersion contribution to the binding energies between molecules and between one molecule and a planar surface.</p>","","","","","","","","","","","","","2014-10-27","2014-10-27","2014-11-04","http://liu.diva-portal.org/smash/get/diva2:758550/FULLTEXT01.pdf","","6","","1","","","","","","false","","","" "763695","Lü, Bo [bolu45] [0000-0002-0908-7187] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Plasma och beläggningsfysik [2225]) (Linköpings universitet [276], Tekniska högskolan [1751]);Elofsson, Viktor [vikjo06] [0000-0003-4811-478X] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Plasma och beläggningsfysik [2225]) (Linköpings universitet [276], Tekniska högskolan [1751]);Münger, Peter [petmu26] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Sarakinos, Kostas [kossa66] [0000-0003-2864-9509] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Plasma och beläggningsfysik [2225]) (Linköpings universitet [276], Tekniska högskolan [1751])","Dynamic competition between island growth and coalescence in metal-on-insulator deposition","Artikel i tidskrift","Refereegranskat","eng","Applied Physics Letters","0003-6951","published","105","16","","163107-1","163107-5","2014","","","","American Institute of Physics (AIP)","","","","","","10.1063/1.4900575","000344363000073","","","urn:nbn:se:liu:diva-112133","","","","Fysik (103)","","","","<p>The morphology of thin metal films and nanostructures synthesized from the vapor phase on insulating substrates is strongly influenced by the coalescence of islands. Here, we derive analytically the quantitative criterion for coalescence suppression by combining atomistic nucleation theory and a classical model of coalescence. Growth simulations show that using this criterion, a coalescence-free growth regime can be reached in which morphological evolution is solely determined by island nucleation, growth, and impingement. Experimental validation for the ability to control the rate of coalescence using this criterion and navigate between different growth regimes is provided by in situ monitoring of Ag deposition on SiO2. Our findings pave the way for creating thin films and nanostructures that exhibit a wide range of morphologies and physical attributes in a knowledge-based manner.</p>","","","","","","","","","","","","","2014-11-17","2014-11-17","2014-12-09","http://liu.diva-portal.org/smash/get/diva2:763695/FULLTEXT01.pdf","","4","","2","urn:nbn:se:liu:diva-112136","","","","","true","","","" "782754","Karimov, A. R. (Institute for High Temperatures, Russian Academy of Science, Moscow);Yu, M. Y. (Zhejiang University, Hangzhou);Stenflo, Lennart [lenst65] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]) (Umea Univ, Dept Plasma Phys, SE-90187 Umea, Sweden)","Expansion of a cold non-neutral plasma slab","Artikel i tidskrift","Refereegranskat","eng","Physics of Plasmas","1070-664X","published","21","","","122304","","2014","","","","","","","","","","10.1063/1.4903879","000347162700029","","","urn:nbn:se:liu:diva-113553","","","","Fysik (103)","","","<p>This work was supported by the National Natural Science Foundation of China (11205194, 11247007, 11374262), ITER-CN (2013GB104004), and the Open Fund of the State Key Laboratory of High Field Laser Physics at SIOM.</p>","<p>Expansion of the ion and electron fronts of a cold non-neutral plasma slab with a quasi-neutral core bounded by layers containing only ions is investigated analytically and exact solutions are obtained. It is found that on average, the plasma expansion time scales linearly with the initial inverse ion plasma frequency as well as the degree of charge imbalance, and no expansion occurs if the cold plasma slab is stationary and overall neutral. However, in both cases, there can exist prominent oscillations on the electron front.</p>","","","","","","","","","","","","","2015-01-22","2015-01-22","2015-02-24","http://liu.diva-portal.org/smash/get/diva2:782754/FULLTEXT01.pdf","","3","","1","","","","","","false","","","" "782756","Mendonca, J. T. (Instituto Superior Técnico, Lisboa);Onishchenko, O G (Institute of Physics of the Earth, Moscow, Russia);Pokhotelov, O A (Institute of Physics of the Earth, Moscow, Russia);Stenflo, Lennart [lenst65] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751])","Wave-kinetic description of atmospheric turbulence","Artikel i tidskrift","Refereegranskat","eng","Physica Scripta","0031-8949","published","89","","","125004","","2014","","","","","","","","","","10.1088/0031-8949/89/12/125004","000347960500005","","","urn:nbn:se:liu:diva-113554","","","atmospheric turbulence;wave-kinetic theory;internal gravity waves","Fysik (103)","","","","<p>We propose a wave-kinetic description of atmospheric turbulence, where the turbulence spectrum is described as a gas of quasi-particles. We apply this description to the case of zonal structures in the atmosphere, which can be excited by internal gravity wave turbulence. A general expression for the instability growth rates is derived, and the particular example of a nearly mono-kinetic turbulent spectrum is discussed.</p>","","","","","","","","","","","","","2015-01-22","2015-01-22","2015-02-16","","","4","","1","","","","","","false","","","" "782751","Brodin, G. (Umea Univ, Dept Phys, SE-90187 Umea, Sweden);Stenflo, Lennart [lenst65] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751])","Nonlinear dynamics of large amplitude modes in a magnetized plasma","Artikel i tidskrift","Refereegranskat","eng","Physics of Plasmas","1070-664X","published","21","","","122301","","2014","","","","","","","","","","10.1063/1.4903326","000347162700026","","","urn:nbn:se:liu:diva-113551","","","","Fysik (103)","","","","<p>We derive two equations describing the coupling between electromagnetic and electrostaticoscillations in one-dimensional geometry in a magnetized cold and non-relativistic plasma. The nonlinear interaction between the wave modes is studied numerically. The effects of the external magnetic field strength and the initial electromagneticpolarization are of particular interest here. New results can, thus, be identified.</p>","","","","","","","","","","","","","2015-01-22","2015-01-22","2015-02-06","http://liu.diva-portal.org/smash/get/diva2:782751/FULLTEXT01.pdf","","2","","1","","","","","","false","","","" "765658","Pourovskii, Leonid [leopo41] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]) (École Polytechnique, Palaiseau, France) (Swedish e-science Research Centre (SeRC));Mravlje, J. (Jozef Stefan Institute, Ljubljana, Slovenija);Ferrero, M. (École Polytechnique, Palaiseau, France);Parcollet, O. (Institut de Physique Théorique (IPhT), CEA, CNRS, URA 2306, Gif-sur-Yvette, France);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751])","Impact of electronic correlations on the equation of state and transport in epsilon-Fe","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","published","90","15","","155120","","2014","","","","American Physical Society","","","","","","10.1103/PhysRevB.90.155120","000343699700001","","","urn:nbn:se:liu:diva-112304","","","","Fysik (103)","","","<p>Funding Agencies|Russian Federation Ministry for Science and Education [14.Y26.31.0005]; Swedish Foundation for Strategic Research (SSF) [10-0026]; PHD DALEN Project [26228RM]; College de France; Slovenian Research Agency program [P1-0044]; ERC [278472]</p>","<p>We have obtained the equilibrium volumes, bulk moduli, and equations of state of the ferromagnetic cubic alpha and paramagnetic hexagonal epsilon phases of iron in close agreement with experiment using an ab initio dynamical mean-field-theory approach. The local dynamical correlations are shown to be crucial for a successful description of the ground-state properties of paramagnetic epsilon-Fe. Moreover, they enhance the effective mass of the quasiparticles and reduce their lifetimes across the alpha -greater than epsilon transition, leading to a stepwise increase of the resistivity, as observed in experiment. The calculated magnitude of the jump is significantly underestimated, which points to nonlocal correlations. The implications of our results for the superconductivity and non-Fermi-liquid behavior of epsilon-Fe are discussed.</p>","","","","","","","","","","","","","2014-11-24","2014-11-24","2014-11-28","http://liu.diva-portal.org/smash/get/diva2:765658/FULLTEXT01.pdf","","5","","2","","","","","","true","","","" "778257","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])","Electromagnetic normal modes and Casimir effects in layered structures","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","published","90","15","","155457","","2014","","","","American Physical Society","","","","","","10.1103/PhysRevB.90.155457","000345636400007","","","urn:nbn:se:liu:diva-113065","","","","Fysik (103)","","","","<p>We derive a general procedure for finding the electromagnetic normal modes in layered structures. We apply this procedure to planar, spherical, and cylindrical structures. These normal modes are important in a variety of applications. They are the only input needed in calculations of Casimir interactions. We present an explicit expression for the condition for modes and Casimir energy for a large number of specific geometries. The layers are allowed to be two-dimensional so graphene and graphenelike sheets as well as two-dimensional electron gases can be handled within the formalism. Also, forces on atoms in layered structures are obtained. One side result is the van der Waals and Casimir-Polder interaction between two atoms.</p>","","","","","","","","","","","","","2015-01-08","2015-01-09","2015-01-15","http://liu.diva-portal.org/smash/get/diva2:778257/FULLTEXT01.pdf","","1","","2","","","","","","false","","","" "765655","Tal, Alexey [aleta94] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Münger, Peter [petmu26] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (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]);Brenning, Nils [nilbr83] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Plasma och beläggningsfysik [2225]) (Linköpings universitet [276], Tekniska högskolan [1751]);Pilch, Iris [iripi77] [0000-0003-3767-225X] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Plasma och beläggningsfysik [2225]) (Linköpings universitet [276], Tekniska högskolan [1751]);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 högskolan [1751])","Molecular dynamics simulation of the growth of Cu nanoclusters from Cu ions in a plasma","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","published","90","16","","165421","","2014","","","","American Physical Society","","","","","","10.1103/PhysRevB.90.165421","000343699900005","","","urn:nbn:se:liu:diva-112305","","","","Fysik (103)","","","<p>Funding Agencies|Knut and Alice Wallenberg Foundation [2012.0083]; Swedish Foundation for Strategic Research (SSF) [10-0026]; Russian Federation Ministry for Science and Education [14.Y26.31.0005]</p>","<p>A recently developed method of nanoclusters growth in a pulsed plasma is studied by means of molecular dynamics. A model that allows one to consider high-energy charged particles in classical molecular dynamics is suggested, and applied for studies of single impact events in nanoclusters growth. In particular, we provide a comparative analysis of the well-studied inert gas aggregation method and the growth from ions in a plasma. The importance to consider of the angular distribution of incoming ions in the simulations of the nanocluster growth is underlined. A detailed study of the energy transfer from the incoming ions to a nanocluster, as well as the diffusion of incoming ions on the cluster surface, is carried out. Our results are important for understanding and control of the nanocluster growth process.</p>","","","","","","","","","","","","","2014-11-24","2014-11-24","2015-05-04","http://liu.diva-portal.org/smash/get/diva2:765655/FULLTEXT02.pdf","","6","","2","","","","","","false","","","" "766756","Hellman, Olle [olohe96] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Broido, David A. (Boston Coll, MA 02467 USA)","Phonon thermal transport in Bi2Te3 from first principles","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","published","90","13","","134309","","2014","","","","American Physical Society","","","","","","10.1103/PhysRevB.90.134309","000343944100002","","","urn:nbn:se:liu:diva-112479","","","","Fysik (103)","","","<p>Funding Agencies|Knut and Alice Wallenberg Foundation (KAW) project ""Isotopic Control for Ultimate Material Properties""; Swedish Foundation for Strategic Research (SSF) [SRL10-002]; S3TEC; U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences [DE-SC0001299/DE-FG02-09ER46577]</p>","<p>We present first-principles calculations of the thermal and thermal transport properties of Bi2Te3 that combine an ab initio molecular dynamics (AIMD) approach to calculate interatomic force constants (IFCs) along with a full iterative solution of the Peierls-Boltzmann transport equation for phonons. The newly developed AIMD approach allows determination of harmonic and anharmonic interatomic forces at each temperature, which is particularly appropriate for highly anharmonic materials such as Bi2Te3. The calculated phonon dispersions, heat capacity, and thermal expansion coefficient are found to be in good agreement with measured data. The lattice thermal conductivity, kappa(l), calculated using the AIMD approach nicely matches measured values, showing better agreement than the kappa(l) obtained using temperature-independent IFCs. A significant contribution to kappa(l) from optic phonon modes is found. Already at room temperature, the phonon line shapes show a notable broadening and onset of satellite peaks reflecting the underlying strong anharmonicity.</p>","","","","","","","","","","","","","2014-11-28","2014-11-28","2014-12-02","http://liu.diva-portal.org/smash/get/diva2:766756/FULLTEXT01.pdf","","2","","2","","","","","","false","","","" "778302","Miranda, Alonso L. (CINVESTAV, Mexico; University of Liege, Belgium);Xu, Bin (University of Liege, Belgium; University of Arkansas, AR 72701 USA; University of Arkansas, AR 72701 USA);Hellman, Olle [olohe96] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Romero, Aldo H. (CINVESTAV, Mexico; W Virginia University, WV 26506 USA);Verstraete, Matthieu J. (University of Liege, Belgium)","Ab initio calculation of the thermal conductivity of indium antimonide","Artikel i tidskrift","Refereegranskat","eng","Semiconductor Science and Technology","0268-1242","published","29","12","","124002","","2014","","","","IOP Publishing: Hybrid Open Access","","","","","","10.1088/0268-1242/29/12/124002","000345454900004","","","urn:nbn:se:liu:diva-113054","","","thermal conductivity; InSb; ab initio; Boltzmann equation; anhamonicity","Fysik (103)","","","<p>Funding Agencies|Knut and Alice Wallenberg Foundation (KAW); Swedish Foundation for Strategic Research (SSF) [SRL10-002]; National Science Foundation [OCI-1053575]; National Science Foundation EPSCoR Research Infrastructure Improvement [1003907]; state of West Virginia (WVEPSCoR via the Higher Education Policy Commission); European Union [PIIFR-GA-2011-911070]; Donors of the American Chemical Society Petroleum Research Fund [54075-ND10]; ARC grant from the Communaute Francaise de Belgique [10/15-03]; University of Liege; CONACyT of Mexico; WVU</p>","<p>A theoretical study based on the density functional theory and the temperature-dependent effective potential method is performed to analyze the changes in the phonon band structure as a function of temperature for indium antimonide. In particular, we show changes in the thermal expansion coefficient and the thermal resistivity that agree rather well with experimental measurements. From the theoretical side, we show a weak dependence with respect to the chosen thermostat used to obtain the inter-atomic force constants, which strengthens our conclusions.</p>","","","","","","","","","","","","","2015-01-08","2015-01-09","2015-01-09","","","5","","1","","","","","","false","","","" "778289","Thiyam, Priyadarshini (Royal Institute Technology, Sweden);Persson, C. (Royal Institute Technology, Sweden; University of Oslo, Norway; University of Oslo, Norway);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]);Bostrom, Mathias (University of Oslo, Norway)","Nonperturbative theory for the dispersion self-energy of atoms","Artikel i tidskrift","Refereegranskat","eng","Physical Review A. Atomic, Molecular, and Optical Physics","1050-2947","published","90","5","","054502","","2014","","","","American Physical Society","","","","","","10.1103/PhysRevA.90.054502","000345414100014","","","urn:nbn:se:liu:diva-113058","","","","Fysik (103)","","","<p>Funding Agencies|Research Council of Norway [221469]; Swedish Reseach Council [C0485101]; European Commission</p>","<p>We go beyond the approximate series expansions used in the dispersion theory of finite-size atoms. We demonstrate that a correct, and nonperturbative, theory dramatically alters the dispersion self-energies of atoms. The nonperturbed theory gives as much as 100% corrections compared to the traditional series-expanded theory for the smaller noble gas atoms.</p>","","","","","","","","","","","","","2015-01-08","2015-01-09","2015-01-14","http://liu.diva-portal.org/smash/get/diva2:778289/FULLTEXT01.pdf","","5","","2","","","","","","false","","","" "776826","Ninham, Barry W. (Australian National University, Australia);Bostrom, Mathias (University of Oslo, Norway; Norwegian University of Science and Technology, Norway);Persson, Clas (University of Oslo, Norway; University of Oslo, Norway; Royal Institute Technology, Sweden);Brevik, Iver (Norwegian University of Science and Technology, Norway);Buhmann, Stefan Y. (University of Freiburg, 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])","Casimir forces in a plasma: possible connections to Yukawa potentials","Artikel i tidskrift","Refereegranskat","eng","European Physical Journal D: Atomic, Molecular and Optical Physics","1434-6060","published","68","10","","328","","2014","","","","EDP Sciences: EPJ / Springer Verlag (Germany)","","","","","","10.1140/epjd/e2014-50484-8","000344342100011","","","urn:nbn:se:liu:diva-112830","","","","Fysik (103)","","","<p>Funding Agencies|Research Council of Norway [221469]; Department of Energy and Process Engineering (NTNU, Norway); Swedish Research Council [C0485101]; DFG [BU 1803/3-1]</p>","<p>We present theoretical and numerical results for the screened Casimir effect between perfect metal surfaces in a plasma. We show how the Casimir effect in an electron-positron plasma can provide an important contribution to nuclear interactions. Our results suggest that there is a connection between Casimir forces and nucleon forces mediated by mesons. Correct nuclear energies and meson masses appear to emerge naturally from the screened Casimir-Lifshitz effect.</p>","","","","","","","","","","","","","2014-12-17","2015-01-08","2015-02-25","http://liu.diva-portal.org/smash/get/diva2:776826/FULLTEXT01.pdf","","6","","1","","","","","","false","","","" "789916","Holec, D. (Mt University of Leoben, Austria);Tasnadi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Wagner, P. (Mt University of Leoben, Austria);Friak, M. (Max Planck Institute Eisenforsch GmbH, Germany; Academic Science Czech Republic, Czech Republic);Neugebauer, J. (Max Planck Institute Eisenforsch GmbH, Germany);Mayrhofer, P. H. (Vienna University of Technology, Austria);Keckes, J. (Austrian Academic Science, Austria; Mt University of Leoben, Austria)","Macroscopic elastic properties of textured ZrN-AlN polycrystalline aggregates: From ab initio calculations to grainscale interactions","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","published","90","18","","184106","","2014","","","","American Physical Society","","","","","","10.1103/PhysRevB.90.184106","000348766500001","","","urn:nbn:se:liu:diva-114447","","","","Fysik (103)","","","<p>Funding Agencies|CPU time at the Vienna Scientific Cluster; Academy of Sciences of the Czech Republic; CERIT-SC under the program Centre CERIT Scientific Cloud, part of the Operational Program Research and Development for Innovations [CZ.1.05/3.2.00/08.0144]; START Program of the Austrian Science Fund (FWF) [Y371]; MetaCentrum [LM2010005]</p>","<p>Despite the fast development of computational material modeling, the theoretical description of macroscopic elastic properties of textured polycrystalline aggregates starting from basic principles remains a challenging task. In this study we use a supercell-based approach to obtain the elastic properties of a random solid solution cubic Zr1-x Al-x N system as a function of the metallic sublattice composition and texture descriptors. The employed special quasirandom structures are optimized not only with respect to short-range-order parameters, but also to make the three cubic directions [1 0 0], [0 1 0], and [0 0 1] as similar as possible. In this way, only a small spread of elastic constant tensor components is achieved and an optimum trade-off between modeling of chemical disorder and computational limits regarding the supercell size and calculational time is proposed. The single-crystal elastic constants are shown to vary smoothly with composition, yielding x approximate to 0.5 an alloy constitution with an almost isotropic response. Consequently, polycrystals with this composition are suggested to have Youngs modulus independent of the actual microstructure. This is indeed confirmed by explicit calculations of polycrystal elastic properties, both within the isotropic aggregate limit and with fiber textures with various orientations and sharpness. It turns out that for low AlN mole fractions, the spread of the possible Youngs modulus data caused by the texture variation can be larger than 100 GPa. Consequently, our discussion of Youngs modulus data of cubic Zr1-x Al-x N contains also the evaluation of the texture typical for thin films.</p>","","","","","","","","","","","","","2015-02-20","2015-02-20","2015-02-25","http://liu.diva-portal.org/smash/get/diva2:789916/FULLTEXT01.pdf","","7","","2","","","","","","false","","","" "529121","Ingason, Arni Sigurdur [arnin42] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]);Mockute, Aurelija (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]);Dahlqvist, Martin [marda09] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]);Magnus, F. (Science Institute, University of Iceland, Reykjavik, Iceland);Olafsson, S. (Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavik, Iceland);Arnalds, U. (Department of Physics, Uppsala University, Box 530, S-751 21 Uppsala, Sweden);Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (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]);Hjorvarsson, B. (Department of Physics, Uppsala University, Uppsala, Sweden);Persson, Per O Å [perpe25] [0000-0001-9140-6724] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]);Rosén, Johanna [johro07] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751])","A Nanolaminated Magnetic Phase: Mn₂GaC","Artikel i tidskrift","Refereegranskat","eng","Materials Research Letters","2166-3831","published","2","2","","89","93","2014","","","","Taylor & Francis","","","","","","10.1080/21663831.2013.865105","","","","urn:nbn:se:liu:diva-77774","","","MAX phases;sputtering;transmission electron microscopy (TEM);ab initio calculation","Naturvetenskap (1)","","","<p>On the day of the defence date the status of this article was previous <strong>Manuscript</strong>. The original title of the Manuscript was <em>Magnetic nanoscale laminates from first principles and thin film synthesis</em>.</p>","<p>Layered magnetic materials are fascinating from the point of view of fundamental science as well as applications. Discoveries such as giant magnetoresistance (GMR) in magnetic multilayers have revolutionized data storage and magnetic recording, and concurrently initiated the search for new layered magnetic materials. One group of inherently nanolaminated compounds are the so called M_n+1AX_n (MAX) phases. Due to the large number of isostructural compositions, researchers are exploring the wide range of interesting properties, and not primarily functionalization through optimization of structural quality. Magnetic MAX phases have been discussed in the literature, though this is hitherto an unreported phenomenon. However, such materials would be highly interesting, based on the attractive and useful properties attained with layered magnetic materials to date. Here we present a new MAX phase, (Cr_1–xMn_x)₂GeC, synthesized as thin film in heteroepitaxial form, showing single crystal material with unprecedented structural MAX phase quality. The material was identified using first-principles calculations to study stability of hypothetical MAX phases, in an eort to identify a potentially magnetic material. The theory predicts a variety of magnetic behavior depending on the Mn concentration and Cr/Mn atomic conguration within the sublattice. The analyzed thin films display a magnetic signal well above room temperature and with partly ferromagnetic ordering. These very promising results open up a field of new layered magnetic materials, with high potential for electronics and spintronics applications.</p>","","","","","","","","","","","","","2012-05-29","2012-05-29","2015-03-09","","","11","","1","urn:nbn:se:liu:diva-77775;urn:nbn:se:liu:diva-104764","","","","","true","","","" "681181","Krasilnikov, O M ( National University of Science and Technology MISIS, Russia );Belov, M P (National University of Science and Technology MISIS, Russia );Lugovskoy, A V (National University of Science and Technology MISIS, Russia );Yu Mosyagin, Igor [igomo87] (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 );Kh Vekilov, Yu (National University of Science and Technology MISIS, Russia )","Elastic properties, lattice dynamics and structural transitions in molybdenum at high pressures","Artikel i tidskrift","Refereegranskat","eng","Computational materials science","0927-0256","published","81","","","313","318","2014","","","","Elsevier","","","","","","10.1016/j.commatsci.2013.08.038","000326940300045","","","urn:nbn:se:liu:diva-102711","","","Phase transitions;Elasticity;High-pressure;Computer simulations;Phonons","Teknik och teknologier (2)","","","<p>Funding Agencies|Ministry of Education and Science of Russian Federation|14.A18.21.0893|Russian Foundation For Basic Research|10-02-0015613-02-00338|</p>","<p>The structural phase transitions in molybdenum under pressures are investigated on the basis of first principle analysis of elastic constants behavior and phonon dispersions. The definition of the effective elastic constants of nth order ( nP2), governing the elastic properties of a loaded crystal, is given. The effective elastic constants of second and third order and the phonon dispersions are calculated by DFT methods in the pressure range of P = 0 - 1400 GPa, T = 0 K. The calculation results at P = 0 are in good agreement with the available experimental data. On the basis of the obtained results the stability of the bcc phase of molybdenum under pressure and the possibility of the phase transition are investigated. It is shown that the effective elastic constant eC0 which corresponds to the tetragonal uniform strain of a loaded crystal undergoes significant softening at P andgt; 400 GPa. In the same pressure range the frequencies of the transverse branch T-[110](-) [zeta zeta 0] also begin to soften and already at P approximate to 1000 GPa they become imaginary near the wave vector [1/4 1/4 0]. The bcc -andgt; dhcp phase transition associated with the softening of eC0 and the soft mode T-[110](-)[1/4 1/4 0] is discussed.</p>","","","","","","","","","","","","","2013-12-19","2013-12-19","2013-12-19","","","5","","1","","","","","","false","","","" "685655","Ponomareva, A V ( National University of Science and Technology MISIS, Russia );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])","Effect of Re content on elastic properties of B2 NiAl from ab initio calculations","Artikel i tidskrift","Refereegranskat","eng","Journal of Alloys and Compounds","0925-8388","published","586","","","S274","S278","2014","","","","Elsevier","","","","","","10.1016/j.jallcom.2012.12.103","000328188800057","","","urn:nbn:se:liu:diva-102967","","","Elastic constants;NiAl;Alloying","Teknik och teknologier (2)","","","<p>Funding Agencies|RFBR|10-02-00-194a|Goran Gustafsson Foundation for Research in Natural Sciences and Medicine||Swedish Research Council (VR)||Swedish Foundation for Strategic Research (SSF) Program in Materials Science for Nanoscale Surface Engineering||</p>","<p>The effect of substitutional alloying of Re on elastic properties of B2 NiAl has been studied using first-principles electronic-structure calculations by the exact muffin-tin orbitals method and the coherent potential approximation. Our calculations have shown that elastic constants C-12, C-44 and bulk modulus B of (Ni1-xRex) Al alloys increase with Re composition almost linearly, but concentration dependence of elastic constants C-11, Young modulus E, shear modulus G, G/B ratio and the Cauchy pressure P-C is strongly nonmonotonously and has peculiarities near the concentration x = 30 at.% Re. Analyzing the density of states and Fermi surface sections we have a direct connection between the behavior of the elastic constants of (Ni1-xRex) Al alloys and changes in the interatomic bonding and Fermi surface topology.</p>","","","","","","","","","","","","","2014-01-09","2014-01-09","2014-03-26","http://liu.diva-portal.org/smash/get/diva2:685655/FULLTEXT01.pdf","","3","","1","","","","","","false","","","" "703372","Palumbo, M. ( Ruhr University of Bochum, Germany );Burton, B. (NIST, MD 20899 USA );Costa e Silva, A. (EEIMVR UFF, Brazil );Fultz, B. (CALTECH, CA 91125 USA );Grabowski, B. (Max Planck Institute Eisenforsch GmbH, Germany );Grimvall, G. (KTH Royal Institute Technology, Sweden );Hallstedt, B. (Rhein Westfal TH Aachen, Germany );Hellman, Olle [olohe96] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Lindahl, B. (KTH Royal Institute Technology, Sweden );Schneider, A. (Vallourec Deutschland GmbH, Germany );Turchi, P. E. A. (Lawrence Livermore National Lab, CA USA );Xiong, W. (University of Wisconsin, WI 53706 USA )","Thermodynamic modelling of crystalline unary phases","Artikel i tidskrift","Refereegranskat","eng","Physica status solidi. B, Basic research","0370-1972","published","251","1","","14","32","2014","","","","Wiley-VCH Verlag","","","","","","10.1002/pssb.201350133","000330784600003","","","urn:nbn:se:liu:diva-105040","","","CALPHAD; crystalline phases; first-principles; thermodynamics","Teknik och teknologier (2)","","","","<p>Progress in materials science through thermodynamic modelling may rest crucially on access to a database, such as that developed by Scientific Group Thermodata Europe (SGTE) around 1990. It gives the Gibbs energy G(T) of the elements in the form of series as a function of temperature, i.e. essentially a curve fitting to experimental data. In the light of progress in theoretical understanding and first-principles calculation methods, the possibility for an improved database description of the thermodynamics of the elements has become evident. It is the purpose of this paper to provide a framework for such work. Lattice vibrations, which usually give the major contribution to G(T), are treated in some detail with a discussion of neutron scattering studies of anharmonicity in aluminium, first-principles calculations including ab initio molecular dynamics (AIMD), and the strength and weakness of analytic model representations of data. Similarly, electronic contributions to G(T) are treated on the basis of the density of states N(E) for metals, with emphasis on effects at high T. Further, we consider G(T) below 300K, which is not covered by SGTE. Other parts in the paper discuss metastable and dynamically unstable lattices, G(T) in the region of superheated solids and the requirement on a database in the calculation of phase diagrams. (C) 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim</p>","","","","","","","","","","","","","2014-03-06","2014-03-06","2014-03-06","","","12","","1","","","","","","false","","","" "703370","Hammerschmidt, T. ( Ruhr University of Bochum, Germany );Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Alfe, D. (UCL, England UCL, England );Fries, S. G. (Ruhr University of Bochum, Germany );Hoglund, L. (KTH Royal Institute Technology, Sweden );Jacobs, M. H. G. (Technical University of Clausthal, Germany );Kossmann, J. (Ruhr University of Bochum, Germany );Lu, X-G. (Shanghai University, Peoples R China );Paul, G. (ThyssenKrupp Steel Europe, Germany )","Including the effects of pressure and stress in thermodynamic functions","Artikel i tidskrift","Refereegranskat","eng","Physica status solidi. B, Basic research","0370-1972","published","251","1","","81","96","2014","","","","Wiley-VCH Verlag","","","","","","10.1002/pssb.201350156","000330784600006","","","urn:nbn:se:liu:diva-105041","","","CALPHAD; DFT calculations; elastic constants; pressure; strain","Teknik och teknologier (2)","","","","<p>Most applications of thermodynamic databases to materials design are limited to ambient pressure. The consideration of elastic contributions to thermodynamic stability is highly desirable but not straight-forward to realise. We present examples of existing physical models for pressure-dependent thermodynamic functions and discuss the requirements for future implementations given the existing results of experiments and first-principles calculations. We briefly summarize the calculation of elastic constants and point out examples of nonlinear variation with pressure, temperature and chemical composition that would need to be accounted for in thermodynamic databases. This is particularly the case if a system melts from different phases at different pressures. Similar relations exist between pressure and magnetism and hence set the need to also include magnetic effects in thermodynamic databases for finite pressure. We present examples to illustrate that the effect of magnetism on stability is strongly coupled to pressure, temperature, and external fields. As a further complication we discuss dynamical instabilities that may appear at finite pressure. While imaginary phonon frequencies may render a structure unstable and destroy a crystal lattice, the anharmonic effects may stabilize it again at finite temperature. Finally, we also outline a possible implementation scheme for strain effects in thermodynamic databases.</p>","","","","","","","","","","","","","2014-03-06","2014-03-06","2014-03-25","http://liu.diva-portal.org/smash/get/diva2:703370/FULLTEXT01.pdf","","9","","1","","","","","","false","","","" "703369","Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Nikonov, A. Yu (Russian Academic Science, Russia );Ponomareva, A. V. (National University of Science and Technology MISiS, Russia );Dmitriev, A. I. (Russian Academic Science, Russia National Research Tomsk State University, Russia );Barannikova, S. A. (Russian Academic Science, Russia National Research Tomsk State University, Russia )","Theoretical Modeling of Thermodynamic and Mechanical Properties of the Pure Components of Ti and Zr Based Alloys Using the Exact Muffin-Tin Orbitals Method","Artikel i tidskrift","Refereegranskat","eng","Russian Physics Journal","1064-8887","published","56","9","","1030","1038","2014","","","","Springer Verlag (Germany)","","","","","","10.1007/s11182-014-0136-7","000330622100009","","","urn:nbn:se:liu:diva-105042","","","first-principles calculation of electronic structure; stability of crystal structure; elastic constants; Ti;Zr;Nb;V;Mo;and Al","Teknik och teknologier (2)","","","","<p>The exact muffin-tin orbitals (EMTO) method belongs to the third and latest generation of first-principles methods of calculating the electronic structure of materials in the so-called approximation of muffin-tin (MT) orbitals within the framework of the density functional theory. A study has been performed of its applicability for modeling the thermodynamic and mechanical properties of the pure components of Ti and Zr based alloys. The total energies of Ti, Zr, Nb, V, Mo, and Al are calculated in three crystal structures - face-centered cubic (FCC), body-centered cubic (BCC), and hexagonal close-packed (HCP). For all of these elements and crystal structures, we have calculated the theoretical values of the lattice constants, elastic constants, and equations of state. The stable crystal structures have been determined. In all cases, calculations by the EMTO method predict the correct structure of the ground state. For stable structures we compared the obtained results with experiment and with calculations using full potential methods. We have demonstrated the reliability of the EMTO method and conclude that its further application for effective modeling of the properties of disordered alloys based on Ti and Zr is possible.</p>","","","","","","","","","","","","","2014-03-06","2014-03-06","2014-03-25","http://liu.diva-portal.org/smash/get/diva2:703369/FULLTEXT01.pdf","","5","","1","","","","","","false","","","" "705029","Stenflo, Lennart [lenst65] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Brodin, G. (Umeå University, Sweden )","Collisional contribution to stimulated scattering in plasmas","Artikel i tidskrift","Refereegranskat","eng","Physics Letters A","0375-9601","published","378","5-6","","549","550","2014","","","","Elsevier","","","","","","10.1016/j.physleta.2013.12.027","000330916300017","","","urn:nbn:se:liu:diva-105252","","","Magnetized plasma; Stimulated scattering; Collisional effects","Teknik och teknologier (2)","","","","<p>The influence of collisions on stimulated Brillouin scattering in magnetized plasmas is discussed. It is shown that new effects occur when the magnitude of the electron quiver velocity exceeds the electron thermal velocity.</p>","","","","","","","","","","","","","2014-03-14","2014-03-14","2014-03-14","","","2","","1","","","","","","false","","","" "708868","Klimchitskaya, G. L. ( Russian Academic Science, Russia St Petersburg State Polytech University, Russia );Mostepanenko, V.M. (Russian Academic Science, Russia St Petersburg State Polytech University, Russia );Sernelius, Bo [bose02] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751])","Two approaches for describing the Casimir interaction in graphene: Density-density correlation function versus polarization tensor","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","published","89","12","","125407","","2014","","","","American Physical Society","","","","","","10.1103/PhysRevB.89.125407","000332458700003","","","urn:nbn:se:liu:diva-105570","","","","Teknik och teknologier (2)","","","","<p>A comparison study of theoretical approaches to the description of the Casimir interaction in layered systems including graphene is performed. It is shown that at zero temperature, the approach using the polarization tensor leads to the same results as the approach using the longitudinal density-density correlation function of graphene. An explicit expression for the zero-temperature transverse density-density correlation function of graphene is provided. We further show that the computational results for the Casimir free energy of graphene-graphene and graphene-Au plate interactions at room temperature, obtained using the temperature-dependent polarization tensor, deviate significantly from those using the longitudinal density-density correlation function defined at zero temperature. We derive both the longitudinal and transverse density-density correlation functions of graphene at nonzero temperature. The Casimir free energy in layered structures including graphene, computed using the temperature-dependent correlation functions, is exactly equal to that found using the polarization tensor.</p>","","","","","","","","","","","","","2014-03-27","2014-03-31","2014-04-08","http://liu.diva-portal.org/smash/get/diva2:708868/FULLTEXT01.pdf","","3","","2","","","","","","false","","","" "714195","Pedersen, Morten [morpe47] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Hedegard, Erik D. (University of Southern Denmark, Denmark );Olsen, Jogvan Magnus H. (University of Southern Denmark, Denmark );Kauczor, Joanna [joaka07] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Beräkningsfysik [2208]) (Linköpings universitet [276], Tekniska högskolan [1751]);Norman, Patrick [patno81] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Beräkningsfysik [2208]) (Linköpings universitet [276], Tekniska högskolan [1751]);Kongsted, Jacob (University of Southern Denmark, Denmark )","Damped Response Theory in Combination with Polarizable Environments: The Polarizable Embedding Complex Polarization Propagator Method","Artikel i tidskrift","Refereegranskat","eng","Journal of Chemical Theory and Computation","1549-9618","published","10","3","","1164","1171","2014","","","","American Chemical Society","","","","","","10.1021/ct400946k","000332913500026","","","urn:nbn:se:liu:diva-106098","","","","Teknik och teknologier (2)","","","","<p>We present a combination of the polarizable embedding (PE) scheme with the complex polarization propagator (CPP) method with the aim of calculating response properties including relaxation for large and complex systems. This new approach, termed PE-CPP, will benefit from the highly advanced description of the environmental electrostatic potential and polarization in the PE method as well as the treatment of near-resonant effects in the CPP approach. The PE-CPP model has been implemented in a Kohn-Sham density functional theory approach, and we present pilot calculations exemplifying the implementation for the UV/vis and carbon K-edge X-ray absorption spectra of the protein plastocyanin. Furthermore, technical details associated with a PE-CPP calculation are discussed.</p>","","","","","","","","","","","","","2014-04-24","2014-04-25","2016-04-28","","","6","","1","urn:nbn:se:liu:diva-127496","","","","","false","","","" "783087","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);Simon, Tamas (Budapest University of Technology and Econ, Hungary);Maze, Jeronimo R. (Pontificia University of Catolica Chile, Chile);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);Gali, Adam (Hungarian Academic Science, Hungary; Budapest University of Technology and Econ, Hungary)","Pressure and temperature dependence of the zero-field splitting in the ground state of NV centers in diamond: A first-principles study","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","published","90","23","","235205","","2014","","","","American Physical Society","","","","","","10.1103/PhysRevB.90.235205","000346860700002","","","urn:nbn:se:liu:diva-113573","","","","Fysik (103)","","","<p>Funding Agencies|NIIF Supercomputer center [1090]; EU [270197, 611143]; Hungarian Academy of Sciences; Knut and Alice Wallenberg Foundation; Swedish National Infrastructure for Computing [SNIC 001/12-275, SNIC 2013/1-331]; Conicyt (Chile) Fondecyt [1141185, PIA ACT1108, PIA ACT1112]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Tomsk State University</p>","<p>Nitrogen-vacancy centers in diamond (NV) attract great attention because they serve as a tool in many important applications. The NV center has a polarizable spin S = 1 ground state and its spin state can be addressed by optically detected magnetic resonance (ODMR) techniques. The m(S) = 0 and m(S) = +/- 1 spin levels of the ground state are separated by about 2.88 GHz in the absence of an external magnetic field or any other perturbations. This zero-field splitting (ZFS) can be probed by ODMR. As this splitting changes as a function of pressure and temperature, the NV center might be employed as a sensor operating at the nanoscale. Therefore, it is of high importance to understand the intricate details of the pressure and temperature dependence of this splitting. Here we present an ab initio theory of the ZFS of the NV center as a function of external pressure and temperature including detailed analysis on the contributions of macroscopic and microscopic effects. We found that the pressure dependence is governed by the change in the distance between spins as a consequence of the global compression and the additional local structural relaxation. The local structural relaxation contributes to the change of ZFS with the same magnitude as the global compression. In the case of temperature dependence of ZFS, we investigated the effect of macroscopic thermal expansion as well as the consequent change of the microscopic equilibrium positions. We could conclude that theses effects are responsible for about 15% of the observed decrease of ZFS.</p>","","","","","","","","","","","","","2015-01-23","2015-01-23","2016-10-11","http://liu.diva-portal.org/smash/get/diva2:783087/FULLTEXT01.pdf","","5","","2","urn:nbn:se:liu:diva-131853","","","","","false","","","" "741597","Ivády, Viktor [vikiv58] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Armiento, Rickard [ricar47] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Szasz, Krisztian (Hungarian Academic Science, Hungary Eotvos Lorand University, Hungary );Janzén, Erik [erija14] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska högskolan [1751]);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 högskolan [1751])","Theoretical unification of hybrid-DFT and DFT plus U methods for the treatment of localized orbitals","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","published","90","3","","035146","","2014","","","","American Physical Society","","","","","","10.1103/PhysRevB.90.035146","000339974700005","","","urn:nbn:se:liu:diva-109879","","","","Fysik (103);Kemi (104)","","","<p>Funding Agencies|Knut and Alice Wallenberg Foundation ""Isotopic Control for Ultimate Materials Properties""; Swedish Research Council (VR) Grants [621-2011-4426, 621-2011-4249]; Swedish Foundation for Strategic Research program SRL Grant [10-0026]; Swedish National Infrastructure for Computing Grants [SNIC 001/12-275, SNIC 2013/1-331]; ""Lendulet program"" of Hungarian Academy of Sciences; U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences [DE-AC02-06CH11357]; Linnaeus Environment at Linkoping on Nanoscale Functional Materials (LiLi-NFM) - VR</p>","<p>Hybrid functionals serve as a powerful practical tool in different fields of computational physics and quantum chemistry. On the other hand, their applicability for the case of correlated d and f orbitals is still questionable and needs more considerations. In this article we formulate the on-site occupation dependent exchange correlation energy and effective potential of hybrid functionals for localized states and connect them to the on-site correction term of the DFT+ U method. The resultant formula indicates that the screening of the onsite electron repulsion is governed by the ratio of the exact exchange in hybrid functionals. Our derivation provides a theoretical justification for adding a DFT+ U-like on-site potential in hybrid-DFT calculations to resolve issues caused by overscreening of localized states. The resulting scheme, hybrid DFT+ V-w, is tested for chromium impurity in wurtzite AlN and vanadium impurity in 4H-SiC, which are paradigm examples of systems with different degrees of localization between host and impurity orbitals.</p>","","","","","","","","","","","","","2014-08-28","2014-08-28","2016-10-11","http://liu.diva-portal.org/smash/get/diva2:741597/FULLTEXT01.pdf","","6","","2","urn:nbn:se:liu:diva-131853","","","","","false","","","" "698186","Castelletto, S. ( RMIT University, Australia );Johnson, B. C. (University of Melbourne, Australia Japan Atom Energy Agency, Japan );Ivády, Viktor [vikiv58] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Stavrias, N. (University of Melbourne, Australia );Umeda, T. (University of Tsukuba, Japan );Gali, A. (Hungarian Academic Science, Hungary Budapest University of Technology and Econ, Hungary );Ohshima, T. (Japan Atom Energy Agency, Japan )","A silicon carbide room-temperature single-photon source","Artikel i tidskrift","Refereegranskat","eng","Nature Materials","1476-1122","published","13","2","","151","156","2014","","","","Nature Publishing Group","","","","","","10.1038/nmat3806","000330182700020","","","urn:nbn:se:liu:diva-104643","","","","Teknik och teknologier (2)","","","","<p>Over the past few years, single-photon generation has been realized in numerous systems: single molecules(1), quantum dots(2-4), diamond colour centres5 and others(6). The generation and detection of single photons play a central role in the experimental foundation of quantum mechanics(7) and measurement theory(8). An efficient and high-quality single-photon source is needed to implement quantum key distribution, quantum repeaters and photonic quantum information processing(9). Here we report the identification and formation of ultrabright, room-temperature, photostable single-photon sources in a device-friendly material, silicon carbide (SiC). The source is composed of an intrinsic defect, known as the carbon antisite-vacancy pair, created by carefully optimized electron irradiation and annealing of ultrapure SiC. An extreme brightness (2 x 10(6) counts s(-1)) resulting from polarization rules and a high quantum efficiency is obtained in the bulk without resorting to the use of a cavity or plasmonic structure. This may benefit future integrated quantum photonic devices(9).</p>","","","","","","","","","","","","","2014-02-20","2014-02-20","2016-10-11","","","7","","2","urn:nbn:se:liu:diva-131853","","","","","false","","","" "762289","Edström, Daniel [daned22] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]);Sangiovanni, Davide G. [davsa82] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (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]);Chirita, Valeriu [valch35] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751])","Effects of atomic ordering on the elastic properties of TiN- and VN-based ternary alloys","Artikel i tidskrift","Refereegranskat","eng","Thin Solid Films","0040-6090","published","571","Part 1","","145","153","2014","","","","Elsevier","","","","","","10.1016/j.tsf.2014.09.048","000346053900024","","","urn:nbn:se:liu:diva-111949","","","Nitrides;Density functional theory;Elastic properties;Ductility;Toughness","Fysik (103)","","","","<p>Improved toughness is one of the central goals in the development of wear-resistant coatings. Previous studies of toughness in transition metal nitride alloys have addressed the effects of chemical composition in these compounds. Herein, we use density functional theory to study the effects of various metal sublattice configurations, ranging from fully ordered to fully disordered, on the mechanical properties of VM2N and TiM2N (M2 = W, Mo) ternary alloys. Results show that all alloys display high incompressibility, indicating strong M-N bonds. Disordered atomic arrangements yield lower values of bulk moduli and C₁₁ elastic constants, as well as higher values of C₄₄ elastic constants, compared to ordered structures. We attribute the low C₄₄ values of ordered structures to the formation of fully-bonding states perpendicular to the applied stress. We find that the ductility of these compounds is primarily an effect of the increased valence electron concentration induced upon alloying.</p>","","","","","","","","","","","","","2014-11-11","2014-11-11","2016-11-07","http://liu.diva-portal.org/smash/get/diva2:762289/FULLTEXT01.pdf","","4","","1","urn:nbn:se:liu:diva-111950;urn:nbn:se:liu:diva-132272","","","","","true","","","" "693011","Elofsson, Viktor [vikjo06] [0000-0003-4811-478X] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Plasma och beläggningsfysik [2225]) (Linköpings universitet [276], Tekniska högskolan [1751]);Magnfält, Daniel [danma73] [0000-0003-0099-5469] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Plasma och beläggningsfysik [2225]) (Linköpings universitet [276], Tekniska högskolan [1751]);Münger, Peter [petmu26] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Sarakinos, Kostas [kossa66] [0000-0003-2864-9509] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Plasma och beläggningsfysik [2225]) (Linköpings universitet [276], Tekniska högskolan [1751])","Unravelling the Physical Mechanisms that Determine Microstructural Evolution of Ultrathin Volmer-Weber Films","Artikel i tidskrift","Refereegranskat","eng","Journal of Applied Physics","0021-8979","published","116","4","","044302","","2014","","","","","","","","","","10.1063/1.4890522","000340710700078","","","urn:nbn:se:liu:diva-103920","","","","Fysik (103)","","","","<p>The initial formation stages (i.e., island nucleation, island growth, and island coalescence) set characteristic length scales during growth of thin films from the vapour phase. They are, thus, decisive for morphological and microstructural features of films and nanostructures. Each of the initial formation stages has previously been well-investigated separately for the case of Volmer-Weber growth, but knowledge on how and to what extent each stage individually and all together affect the microstructural evolution is still lacking. Here we address this question using growth of Ag on SiO₂ from pulsed vapour fluxes as a case study. By combining in situ growth monitoring, ex situ imaging and growth simulations we systematically study the growth evolution all the way from nucleation to formation of a continuous film and establish the effect of the vapour flux time domain on the scaling behaviour of characteristic growth transitions (elongation transition, percolation and continuous film formation). Our data reveal a pulsing frequency dependence for the characteristic film growth transitions, where the nominal transition thickness decreases with increasing pulsing frequency up to a certain value after which a steady-state behaviour is observed. The scaling behaviour is shown to result from differences in island sizes and densities, as dictated by the initial film formation stages. These differences are determined solely by the interplay between the characteristics of the vapour flux and time required for island coalescence to be completed. In particular, our data provide evidence that the steady-state scaling regime of the characteristic growth transitions is caused by island growth that hinders coalescence from being completed, leading to a coalescence-free growth regime.</p>","","","","","","","","","","","","","2014-02-03","2014-02-03","2016-11-30","http://liu.diva-portal.org/smash/get/diva2:693011/FULLTEXT01.pdf","","4","","2","urn:nbn:se:liu:diva-103921;urn:nbn:se:liu:diva-105791;urn:nbn:se:liu:diva-112136;urn:nbn:se:liu:diva-132895","","","","","false","","","" "751997","Lindmaa, Alexander [aleli16] [0000-0001-5439-711X] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Mattsson, A. E. (Sandia National Labs, NM 87185 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 högskolan [1751])","Quantum oscillations in the kinetic energy density: Gradient corrections from the Airy gas","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","1550-235X","published","90","7","","075139","","2014","","","","American Physical Society","","","","","","","10.1103/PhysRevB.90.075139","000341238200002","","","urn:nbn:se:liu:diva-110971","","","","Den kondenserade materiens fysik (10304)","","","<p>Funding Agencies|Swedish Research Council (VR) [621-2011-4249]; Linnaeus Environment at Linkoping on Nanoscale Functional Materials (LiLi-NFM) - VR; U.S. Department of Energys National Nuclear Security Administration [DE-AC04-94AL85000]</p>","<p>We derive a closed-form expression for the quantum corrections to the kinetic energy density in the Thomas-Fermi limit of a linear potential model system in three dimensions (the Airy gas). The universality of the expression is tested numerically in a number of three-dimensional model systems: (i) jellium surfaces, (ii) confinement in a hydrogenlike potential (the Bohr atom), (iii) particles confined by a harmonic potential in one and (iv) all three dimensions, and (v) a system with a cosine potential (the Mathieu gas). Our results confirm that the usual gradient expansion of extended Thomas-Fermi theory does not describe the quantum oscillations for systems that incorporate surface regions where the electron density drops off to zero. We find that the correction derived from the Airy gas is universally applicable to relevant spatial regions of systems of types (i), (ii), and (iv), but somewhat surprisingly not (iii). We discuss possible implications of our findings to the development of functionals for the kinetic energy density.</p>","","","","","","","","","","","","","2014-10-01","2014-10-02","2014-10-22","http://liu.diva-portal.org/smash/get/diva2:751997/FULLTEXT01.pdf","","3","","2","","","","","","false","","","" "705273","Johansson, Leif I. [leijo19] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska högskolan [1751]);Armiento, Rickard [ricar47] [0000-0002-5571-0814] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Avila, Jose (Synchrotron SOLEIL, France );Xia, Chao [chaxi72] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska högskolan [1751]);Lorcy, Stephan (Synchrotron SOLEIL, France );Igor A., Abrikosov [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Asensio, Maria C. (Synchrotron SOLEIL, France );Virojanadara, Chariya [chavi32] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Halvledarmaterial [2218]) (Linköpings universitet [276], Tekniska högskolan [1751])","Multiple π-bands and Bernal stacking of multilayer graphene on C-face SiC, revealed by nano-Angle Resolved Photoemission","Artikel i tidskrift","Refereegranskat","eng","Scientific Reports","2045-2322","","published","4","4157","","","","2014","","","","Nature Publishing Group","","","","","","","10.1038/srep04157","000331885900004","","","urn:nbn:se:liu:diva-105279","","","Electronic properties and materials;Graphene;Stacking","Den kondenserade materiens fysik (10304)","","","","<p>Only a single linearly dispersing π-band cone, characteristic of monolayer graphene, has so far been observed in Angle Resolved Photoemission (ARPES) experiments on multilayer graphene grown on C-face SiC. A rotational disorder that effectively decouples adjacent layers has been suggested to explain this. However, the coexistence of μm-sized grains of single and multilayer graphene with different azimuthal orientations and no rotational disorder within the grains was recently revealed for C-face graphene, but conventional ARPES still resolved only a single π-band. Here we report detailed nano-ARPES band mappings of individual graphene grains that unambiguously show that multilayer C-face graphene exhibits multiple π-bands. The band dispersions obtained close to the K-point moreover clearly indicate, when compared to theoretical band dispersion calculated in the framework of the density functional method, Bernal (AB) stacking within the grains. Thus, contrary to earlier claims, our findings imply a similar interaction between graphene layers on C-face and Si-face SiC.</p>","","","","","","","","","","","","","2014-03-14","2014-03-14","2015-08-28","http://liu.diva-portal.org/smash/get/diva2:705273/FULLTEXT01.pdf","Vetenskapsrådet [621-2011-4252];Vetenskapsrådet [621-2011-4249];Stiftelsen för strategisk forskning (SSF) [10-0026]","8","","1","urn:nbn:se:liu:diva-120893","","","","","true","true","","" "717119","Hao, Feng (Sandia National Laboratories, Albuquerque, New Mexico, 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 högskolan [1751]);Mattsson, Ann E. (Sandia National Laboratories, Albuquerque, New Mexico, USA)","Using the electron localization function to correct for confinement physics in semi-local density functional theory","Artikel i tidskrift","Refereegranskat","eng","Journal of Chemical Physics","0021-9606","1089-7690","published","140","18","","","","2014","","","","American Institute of Physics (AIP)","","","","","","","10.1063/1.4871738","000336782700039","","","urn:nbn:se:liu:diva-106608","","","Crystal structure;density functional theory;Electron gas;Electron Localization Function","Atom- och molekylfysik och optik (10302);Den kondenserade materiens fysik (10304)","","","","<p>We have previously proposed that further improved functionals for density functional theory can be constructed based on the Armiento-Mattsson subsystem functional scheme if, in addition to the uniform electron gas and surface models used in the Armiento-Mattsson 2005 functional, a model for the strongly confined electron gas is also added. However, of central importance for this scheme is an index that identifies regions in space where the correction provided by the confined electron gas should be applied. The electron localization function (ELF) is a well-known indicator of strongly localized electrons. We use a model of a confined electron gas based on the harmonic oscillator to show that regions with high ELF directly coincide with regions where common exchange energy functionals have large errors. This suggests that the harmonic oscillator model together with an index based on the ELF provides the crucial ingredients for future improved semi-local functionals. For a practical illustration of how the proposed scheme is intended to work for a physical system we discuss monoclinic cupric oxide, CuO. A thorough discussion of this system leads us to promote the cell geometry of CuO as a useful benchmark for future semi-local functionals. Very high ELF values are found in a shell around the O ions, and take its maximum value along the Cu–O directions. An estimate of the exchange functional error from the effect of electron confinement in these regions suggests a magnitude and sign that could account for the error in cell geometry.</p>","","","","","","","","","","","","","2014-05-14","2014-05-14","2017-02-28","http://liu.diva-portal.org/smash/get/diva2:717119/FULLTEXT01.pdf","Vetenskapsrådet [621-2011-4249]","3","","1","","","","","18A536","true","","","" "717171","Armiento, Rickard [ricar47] [0000-0002-5571-0814] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Kozinsky, Boris (Research and Technology Center, Robert Bosch LLC, Cambridge, Massachusetts, USA);Hautier, Geoffroy (Université catholique de Louvain, Belgium);Fornari, Marco (Central Michigan University, Mount Pleasant, Michigan, USA);Ceder, Gerbrand (Massachusetts Institute of Technology, Cambridge, USA)","High-throughput screening of perovskite alloys for piezoelectric performance and thermodynamic stability","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","1550-235X","published","89","13","","134103","","2014","","","","American Physical Society","","","","","","","10.1103/PhysRevB.89.134103","000337285000001","","","urn:nbn:se:liu:diva-106609","","","High-throughput;DFT;piezoelectric;thermodynamic stability","Den kondenserade materiens fysik (10304)","","","","<p>We screen a large chemical space of perovskite alloys for systems with optimal properties to accommodate a morphotropic phase boundary (MPB) in their composition-temperature phase diagram, a crucial feature for high piezoelectric performance. We start from alloy end points previously identified in a high-throughput computational search. An interpolation scheme is used to estimate the relative energies between different perovskite distortions for alloy compositions with a minimum of computational effort. Suggested alloys are further screened for thermodynamic stability. The screening identifies alloy systems already known to host an MPB and suggests a few others that may be promising candidates for future experiments. Our method of investigation may be extended to other perovskite systems, e.g., (oxy-)nitrides, and provides a useful methodology for any application of high-throughput screening of isovalent alloy systems.</p>","","","","","","","","","","","","","2014-05-14","2014-05-14","2014-08-14","http://liu.diva-portal.org/smash/get/diva2:717171/FULLTEXT01.pdf","Vetenskapsrådet [621-2011-4249]","5","","2","","","","","","true","","","" "705216","Zhu, Hong (Massachusetts Institute of Technology, Cambridge, USA);Sun, Wenhao (Massachusetts Institute of Technology, Cambridge, 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 högskolan [1751]);Lazić, Predrag (Rudjer Boskovic Institute, Zagreb, Croatia);Ceder, Gerbrand (Massachusetts Institute of Technology, Cambridge, USA)","Band structure engineering through orbital interaction for enhanced thermoelectric power factor","Artikel i tidskrift","Refereegranskat","eng","Applied Physics Letters","0003-6951","1077-3118","published","104","","","082107-1","082107-5","2014","","","","American Institute of Physics (AIP)","","","","","","","10.1063/1.4866861","000332619100064","","","urn:nbn:se:liu:diva-105274","","","Thermoelectrics;Band structure;Power factor;Seebeck effect","Den kondenserade materiens fysik (10304)","","","","<p>Band structure engineering for specific electronic or optical properties is essential for the further development of many important technologies including thermoelectrics, optoelectronics, and microelectronics. In this work, we report orbital interaction as a powerful tool to finetune the band structure and the transport properties of charge carriers in bulk crystalline semiconductors. The proposed mechanism of orbital interaction on band structure is demonstrated for IV-VI thermoelectric semiconductors. For IV-VI materials, we find that the convergence of multiple carrier pockets not only displays a strong correlation with the s-p and spin-orbit coupling but also coincides with the enhancement of power factor. Our results suggest a useful path to engineer the band structure and an enticing solid-solution design principle to enhance thermoelectric performance.</p>","","","","","","","","","","","","","2014-03-14","2014-03-14","2014-04-22","http://liu.diva-portal.org/smash/get/diva2:705216/FULLTEXT01.pdf","Vetenskapsrådet [621-2011-4249]","5","","2","","","","","","true","","","" "739445","Ektarawong, Annop [annek02] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (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]);Birch, Jens [jenbi91] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (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])","First-principles study of configurational disorder in B₄C using a superatom-special quasirandom structure method","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","1550-235X","published","90","2","","","","2014","","","","American Physical Society","","","","","","","10.1103/PhysRevB.90.024204","000339481700003","","","urn:nbn:se:liu:diva-109591","","","","Fysik (103)","","","","<p>Configurationally disordered crystalline boron carbide, with the composition B4C, is studied using first-principles calculations. We investigate both dilute and high concentrations of carbon-boron substitutional defects. For the latter purpose, we suggest a superatoms picture of the complex structure and combine it with a special quasirandom structure approach for disorder. In this way, we model a random distribution of high concentrations of the identified low-energy defects: (1) bipolar defects and (2) rotation of icosahedral carbon among the three polar-up sites. Additionally, the substitutional disorder of the icosahedral carbon at all six polar sites, as previously discussed in the literature, is also considered. Two configurational phase transitions from the ordered to the disordered configurations are predicted to take place upon an increase in temperature using a mean-field approximation for the entropy. The first transition, at 870 K, induces substitutional disorder of the icosahedral carbon atoms among the three polar-up sites; meanwhile the second transition, at 2325 K, reveals the random substitution of the icosahedral carbon atoms at all six polar sites coexisting with bipolar defects. Already the first transition removes the monoclinic distortion existing in the ordered ground-state configuration and restore the rhombohedral system (R3m). The restoration of inversion symmetry yielding the full rhombohedral symmetry (R (3) over barm) on average, corresponding to what is reported in the literature, is achieved after the second transition. Investigating the effects of high pressure on the configurational stability of the disordered B4C phases reveals a tendency to stabilize the ordered ground-state configuration as the configurationally ordering/disordering transition temperature increases with pressure exerted on B4C. The electronic density of states, obtained from the disordered phases, indicates a sensitivity of the band gap to the degree of configurational disorder in B4C.</p>","","","","","","","","","","","","","2014-08-21","2014-08-21","2017-05-16","http://liu.diva-portal.org/smash/get/diva2:739445/FULLTEXT01.pdf","","5","","2","urn:nbn:se:liu:diva-122426;urn:nbn:se:liu:diva-136813","","Conference name","","024204","false","","","" "635739","Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]);Khatibi, Ali [alikh98] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Eklund, Per [perek02] [0000-0003-1785-0864] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (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])","Theoretical investigation of cubic B1-like and corundum (Cr₁₋_<em>x</em>Al_<em>x</em>)₂O₃ solid solutions","Artikel i tidskrift","Refereegranskat","eng","Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films","0734-2101","published","31","3","","","","2013","","","","American Vacuum Society","","","","","","10.1116/1.4795392","000319349900002","","","urn:nbn:se:liu:diva-95510","","","","Teknik och teknologier (2)","","","<p>E A3 05:192||Ingvar Carlsson Award 3||</p>","<p>First-principles calculations are employed to investigate the stability and properties of cubic rock-salt-like (Cr₁₋_<em>x</em>Al_<em>x</em>)₂O₃ solid solutions, stabilized by metal site vacancies as recently reported experimentally. It is demonstrated that the metal site vacancies can indeed be ordered in a way that gives rise to a suitable fourfold coordination of all O atoms in the lattice. B1-like structures with ordered and disordered metal site vacancies are studied for (Cr_0.5Al_0.5)₂O₃ and found to have a cubic lattice spacing close to the values reported experimentally, in contrast to fluorite-like and perovskite structures. The obtained B1-like structures are higher in energy than corundum solid solutions for all compositions, but with an energy offset per atom similar to other metastable systems possible to synthesize with physical vapor deposition techniques. The obtained electronic structures show that the B1-like systems are semiconducting although with smaller band gaps than the corundum structure.</p>","","","","","","","","","","","","","2013-07-05","2013-07-05","2016-08-31","http://liu.diva-portal.org/smash/get/diva2:635739/FULLTEXT01.pdf","","5","","1","","","","","","false","","","" "640759","Pokhotelov, O.A. ( Institute Phys Earth, Russia );Onishchenko, O.G. (Institute Phys Earth, Russia );Stenflo, Lennart [lenst65] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751])","Physical mechanisms for electron mirror and field swelling modes","Artikel i tidskrift","Refereegranskat","eng","Physica Scripta","0031-8949","published","87","6","","065303","","2013","","","","Institute of Physics","","","","","","10.1088/0031-8949/87/06/065303","000319816800011","","","urn:nbn:se:liu:diva-96127","","","","Teknik och teknologier (2)","","","","<p>Ion mirror instability is dominant in planetary and cometary magnetosheaths and other high-beta plasmas where the ions are hotter than the electrons. It is associated with a zero-frequency non-propagating mode with the wave vector nearly perpendicular to the ambient magnetic field. The counterparts of this instability in hot electron plasmas are the field swelling and electron mirror instabilities. A theory for these instabilities was developed more than two decades ago (Basu B and Coppi B 1982 Phys. Rev. Lett. 48 799, 1984 Phys. Fluids 27 1187) within the framework of a fluid model. The connection between the two types of instabilities has been analyzed in (Migliuolo S 1986 J. Geophys. Res. 91 7981). In contrast to these papers, we shall here adopt the standard quasi-hydrodynamic approach that is usually used for the study of mirror instabilities. To analyze the electron mirror and field swelling instabilities, we will only use the perpendicular balance condition and the Liouville theorem. We have found that such a description is easier to understand and gives us increased physical insight into the basic physical features of both these instabilities.</p>","","","","","","","","","","","","","2013-08-14","2013-08-14","2014-01-13","","","3","","1","","","","","","false","","","" "642919","Reeh, S. (Materials Chemistry, RWTH Aachen University, Aachen, Germany);Music, D. (Materials Chemistry, RWTH Aachen University, Aachen, 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 högskolan [1751]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Schneider, J. M. (Materials Chemistry, RWTH Aachen University, Aachen, Germany)","Elastic properties of fcc Fe-Mn-X (X=Cr, Co, Ni, Cu) alloys from first-principles calculations","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","published","87","22","","","","2013","","","","American Physical Society","","","","","","10.1103/PhysRevB.87.224103","000320103700002","","","urn:nbn:se:liu:diva-96471","","","","Teknik och teknologier (2)","","","","<p>The influence of the valence electron concentration of X in fcc Fe-Mn-X (X=Cr, Co, Ni, Cu) alloys on the elastic and magnetic properties has been studied by means of ab initio calculations for alloy element concentrations of up to 8 at. % X. We observe that Cu increases the bulk-to-shear modulus (B/G) ratio by 19.2%. Simultaneously magnetic moments of Fe and Mn increase strongly. The other alloying elements induce less significant changes in B/G. The trends in B/G may be understood by considering the changes in G induced by the variation in valence electron concentration (VEC). As the VEC is increased, more pronounced metallic bonds are formed, giving rise to smaller shear modulus values. The changes in magnetic moments may be explained by the magnetovolume effect. Alloys with smaller VEC as Fe-Mn exhibit a decrease in local magnetic moments and equilibrium lattice parameters, while alloys with larger VEC as Fe-Mn demonstrate an increase in local magnetic moments and equilibrium lattice parameters. These data provide the basis for the design of Mn-rich steels with enhanced elastic properties.</p>","","","","","","","","","","","","","2013-08-20","2013-08-23","2015-08-19","http://liu.diva-portal.org/smash/get/diva2:642919/FULLTEXT01.pdf","","5","","2","","","","","","false","","","" "642922","Vicencio, Rodrigo A. (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 högskolan [1751])","Discrete flat-band solitons in the kagome lattice","Artikel i tidskrift","Refereegranskat","eng","Physical Review A. Atomic, Molecular, and Optical Physics","1050-2947","published","87","6","","","","2013","","","","American Physical Society","","","","","","10.1103/PhysRevA.87.061803","000320764300001","","","urn:nbn:se:liu:diva-96468","","","","Teknik och teknologier (2)","","","","<p>We consider a model for a two-dimensional kagome lattice with defocusing nonlinearity, and show that families of localized discrete solitons may bifurcate from localized linear modes of the flat band with zero power threshold. Each family of such fundamental nonlinear modes corresponds to a unique configuration in the strong-nonlinearity limit. By choosing well-tuned dynamical perturbations, small-amplitude, strongly localized solutions from different families may be switched into each other, as well as moved between different lattice positions. In a window of small power, the lowest-energy state is a symmetry-broken localized state, which may appear spontaneously.</p>","","","","","","","","","","","","","2013-08-20","2013-08-23","2014-01-13","http://liu.diva-portal.org/smash/get/diva2:642922/FULLTEXT01.pdf","","2","","2","","","","","","false","","","" "635787","Reeh, S ( Rhein Westfal TH Aachen, Germany );Kasprzak, M (Rhein Westfal TH Aachen, Germany );Klusmann, C D. (Rhein Westfal TH Aachen, Germany );Stalf, F (Rhein Westfal TH Aachen, Germany );Music, D (Rhein Westfal TH Aachen, 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 högskolan [1751]);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Schneider, J M. (Rhein Westfal TH Aachen, Germany )","Elastic properties of fcc Fe-Mn-X (X = Cr, Co, Ni, Cu) alloys studied by the combinatorial thin film approach and ab initio calculations","Artikel i tidskrift","Refereegranskat","eng","Journal of Physics: Condensed Matter","0953-8984","published","25","24","","","","2013","","","","Institute of Physics: Hybrid Open Access","","","","","","10.1088/0953-8984/25/24/245401","000319673800009","","","urn:nbn:se:liu:diva-95499","","","","Teknik och teknologier (2)","","","<p>Funding Agencies|Deutsche Forschungsgemeinschaft (DFG) within the Collaborative Research Center|(SFB) 761|Swedish Research Council|621-2011-4426|Swedish Foundation for Strategic Research|SRL 10-0026|Swedish e-Science Research Centre (SeRC)||</p>","<p>The elastic properties of fcc Fe-Mn-X (X = Cr, Co, Ni, Cu) alloys with additions of up to 8 at.% X were studied by combinatorial thin film growth and characterization and by ab initio calculations using the disordered local moments (DLM) approach. The lattice parameter and Youngs modulus values change only marginally with X. The calculations and experiments are in good agreement. We demonstrate that the elastic properties of transition metal alloyed Fe-Mn can be predicted by the DLM model.</p>","","","","","","","","","","","","","2013-07-05","2013-07-05","2015-08-19","","","8","","1","","","","","","false","","","" "647349","Sergueev, I. (Deutsches Elektronen-Synchrotron, D-22607 Hamburg, Germany);Dubrovinsky, Leonid (Bayerisches Geoinstitut, Universität Bayreuth, Bayreuth, Germany);Ekholm, Marcus [marek10] [0000-0002-7563-1494] (Linköpings universitet [276], Institutionen för systemteknik [295]) (Linköpings universitet [276], Tekniska högskolan [1751]);Vekilova, Olga [olgve20] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Chumakov, A. I. (European Synchrotron Radiation Facility (ESRF), Grenoble, France);Zając, M. (European Synchrotron Radiation Facility (ESRF), Grenoble, France);Potapkin, V. (European Synchrotron Radiation Facility (ESRF), Grenoble, France);Kantor, I. (European Synchrotron Radiation Facility (ESRF), Grenoble, France);Bornemann, S. (Department of Chemistry, Ludwig-Maximilians-Universität München, München, Germany);Ebert, H. (Department of Chemistry, Ludwig-Maximilians-Universität München, München, Germany);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (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]);Ruffer, R. (European Synchrotron Radiation Facility (ESRF), P.O. Box 220, F-38043 Grenoble, France)","Hyperfine Splitting and Room-Temperature Ferromagnetism of Ni at Multimegabar Pressure","Artikel i tidskrift","Refereegranskat","eng","Physical Review Letters","0031-9007","published","111","15","","","","2013","","","","AMER PHYSICAL SOC","","","","","","10.1103/PhysRevLett.111.157601","000326051100011","","","urn:nbn:se:liu:diva-97381","","","","Teknik och teknologier (2)","","","","<p>Magnetic and elastic properties of Ni metal have been studied up to 260 GPa by nuclear forward scattering of synchrotron radiation with the 67.4 keV Mossbauer transition of Ni-61. The observed magnetic hyperfine splitting confirms the ferromagnetic state of Ni up to 260 GPa, the highest pressure where magnetism in any material has been observed so far. Ab initio calculations reveal that the pressure evolution of the hyperfine field, which features a maximum in the range of 100 to 225 GPa, is a relativistic effect. The Debye energy obtained from the Lamb-Mossbauer factor increases from 33 me V at ambient pressure to 60 me V at 100 GPa. The change of this energy over volume compression is well described by a Gruneisen parameter of 2.09.</p>","","","","","","","","","","","","","2013-09-11","2013-09-11","2015-08-19","http://liu.diva-portal.org/smash/get/diva2:647349/FULLTEXT01.pdf","","13","","2","urn:nbn:se:liu:diva-97383","","","","","true","","","" "647364","Xu, Weiming M. (School of Physics and Astronomy, Tel Aviv University, Tel Aviv, Israel);Greenberg, Eran (Bayerisches Geoinstitut, Universität Bayreuth, Bayreuth, Germany);Rozenberg, Gregory Kh. (School of Physics and Astronomy, Tel Aviv University, Tel Aviv, Israel);Pasternak, Moshe P. (School of Physics and Astronomy, Tel Aviv University, Tel Aviv, Israel);Bykova, Elena (Bayerisches Geoinstitut, University of Bayreuth, Bayreuth, Germany);Boffa-Ballaran, Tiziana (Bayerisches Geoinstitut, University of Bayreuth, Bayreuth, Germany);Dubrovinsky, Leonid (Bayerisches Geoinstitut, Universität Bayreuth, Bayreuth, Germany);Prakapenka, Vitali (Consortium for Advanced Radiation Sources, University of Chicago, Argonne, USA);Hanfland, Michael (European Synchrotron Radiation Facility (ESRF), Grenoble Cedex, France);Vekilova, Olga [olgve20] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (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]);Ruffer, R. (European Synchrotron Radiation Facility (ESRF), P.O. Box 220, F-38043 Grenoble, France)","Pressure-induced hydrogen bond symmetrization in iron oxyhydroxide","Artikel i tidskrift","Refereegranskat","eng","Physical Review Letters","0031-9007","published","111","17","","","","2013","","","","","","","","","","10.1103/PhysRevLett.111.175501","000326148500007","","","urn:nbn:se:liu:diva-97382","","","","Teknik och teknologier (2)","","","","<p>Under high pressures the hydrogen bonds were predicted to transform from a highly asymmetric soft O-H center dot center dot center dot O to a symmetric rigid configuration in which the proton lies midway between the two oxygen atoms. Despite four decades of research on hydroxyl containing compounds, pressure induced hydrogen bond symmetrization remains elusive. Following single crystal x-ray diffraction, Mossbauer and Raman spectroscopy measurements supported by ab initio calculations, we report the H-bonds symmetrization in iron oxyhydroxide, FeOOH, resulting from the Fe3+ high-to-low spin crossover at above 45 GPa.</p>","","","","","","","","","","","","","2013-09-11","2013-09-11","2013-11-28","http://liu.diva-portal.org/smash/get/diva2:647364/FULLTEXT01.pdf","","13","","2","urn:nbn:se:liu:diva-97383","","","","","true","","","" "652293","Jason, Peter [petja31] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Johansson, Magnus [magjo23] [0000-0001-6708-1560] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751])","Quantum dynamics of lattice states with compact support in an extended Bose-Hubbard model","Artikel i tidskrift","Refereegranskat","eng","Physical Review A. Atomic, Molecular, and Optical Physics","1050-2947","published","88","3","","033605","","2013","","","","American Physical Society","","","","","","10.1103/PhysRevA.88.033605","000323942100007","","","urn:nbn:se:liu:diva-98144","","","","Teknik och teknologier (2)","","","<p>Funding Agencies|Swedish Research Council||</p>","<p>We study the dynamical properties, with special emphasis on mobility, of quantum lattice compactons (QLCs) in a one-dimensional Bose-Hubbard model extended with pair-correlated hopping. These are quantum counterparts of classical lattice compactons (localized solutions with exact zero amplitude outside a given region) of an extended discrete nonlinear Schrödinger equation, which can be derived in the classical limit from the extended Bose-Hubbard model. While an exact one-site QLC eigenstate corresponds to a classical one-site compacton, the compact support of classical several-site compactons is destroyed by quantum fluctuations. We show that it is possible to reproduce the stability exchange regions of the one-site and two-site localized solutions in the classical model with properly chosen quantum states. Quantum dynamical simulations are performed for two different types of initial conditions: “localized ground states” which are localized wave packets built from superpositions of compactonlike eigenstates, and SU(4) coherent states corresponding to classical two-site compactons. Clear signatures of the mobility of classical lattice compactons are seen, but this crucially depends on the magnitude of the applied phase gradient. For small phase gradients, which classically correspond to a slow coherent motion, the quantum time scale is of the same order as the time scale of the translational motion, and the classical mobility is therefore destroyed by quantum fluctuations. For a large phase instead, corresponding to fast classical motion, the time scales separate so that a mobile, localized, coherent quantum state can be translated many sites for particle numbers already of the order of 10.</p>","","","","","","","","","","","","","2013-09-30","2013-09-30","2016-08-22","http://liu.diva-portal.org/smash/get/diva2:652293/FULLTEXT01.pdf","","2","","2","urn:nbn:se:liu:diva-105817;urn:nbn:se:liu:diva-129564","","","","","false","","","" "645767","Olovsson, Weine [weiol14] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Weinhardt, L (University of Wurzburg, Germany);Fuchs, O (University of Wurzburg, Germany);Tanaka, I (Kyoto University, Japan);Puschnig, P (University of Leoben, Austria);Umbach, E (University of Wurzburg, Germany);Heske, C (University of Wurzburg, Germany);Draxl, C (University of Leoben, Austria)","The Be K-edge in beryllium oxide and chalcogenides : soft x-ray absorption spectra from first-principles theory and experiment","Artikel i tidskrift","Refereegranskat","eng","Journal of Physics: Condensed Matter","0953-8984","published","25","31","","","","2013","","","","Institute of Physics: Hybrid Open Access","","","","","","10.1088/0953-8984/25/31/315501","000321944000008","","","urn:nbn:se:liu:diva-97251","","","","Teknik och teknologier (2)","","","<p>Funding Agencies|Linkoping Linnaeus Initiative for Novel Functional Materials (LiLi-NFM)||Swedish Research Council (VR)||VR grant|691-2011-4426|Swedish National Infrastructure for Computing (SNIC)||Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan||European Theoretical Spectroscopy Facility (ETSF)||Deutsche Forschungsgemeinschaft|SFB 410|</p>","<p>We have carried out a theoretical and experimental investigation of the beryllium K-edge soft x-ray absorption fine structure of beryllium compounds in the oxygen group, considering BeO, BeS, BeSe, and BeTe. Theoretical spectra are obtained <em>ab initio</em>, through many-body perturbation theory, by solving the Bethe–Salpeter equation (BSE), and by supercell calculations using the core-hole approximation. All calculations are performed with the full-potential linearized augmented plane-wave method. It is found that the two different theoretical approaches produce a similar fine structure, in good agreement with the experimental data. Using the BSE results, we interpret the spectra, distinguishing between bound core-excitons and higher energy excitations.</p>","","","","","","","","","","","","","2013-09-05","2013-09-05","2013-09-11","http://liu.diva-portal.org/smash/get/diva2:645767/FULLTEXT01.pdf","","8","","1","","","","","","true","","","" "656916","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 högskolan [1751])","Alfven wave interactions within the Hall-MHD description","Artikel i tidskrift","Refereegranskat","eng","Journal of Plasma Physics","0022-3778","published","79","","","909","911","2013","","","","Cambridge University Press (CUP)","","","","","","10.1017/S0022377813000640","000324550000056","","","urn:nbn:se:liu:diva-99404","","","","Teknik och teknologier (2)","","","","<p>We show that comparatively simple expressions for the Alfven wave coupling coefficients can be deduced from the well-known Hall-magnetohydrodynamics (MHD) model equations.</p>","","","","","","","","","","","","","2013-10-17","2013-10-17","2014-01-15","http://liu.diva-portal.org/smash/get/diva2:656916/FULLTEXT01.pdf","","2","","1","","","","","","false","","","" "659443","Hellman, Olle [olohe96] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (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])","Temperature-dependent effective third-order interatomic force constants from first principles","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","published","88","14","","","","2013","","","","American Physical Society","","","","","","10.1103/PhysRevB.88.144301","000325181000003","","","urn:nbn:se:liu:diva-100026","","","","Teknik och teknologier (2)","","","<p>Funding Agencies|Knut and Alice Wallenberg Foundation (KAW)||Swedish Foundation for Strategic Research (SSF)|SRL10-002|</p>","<p>The temperature-dependent effective potential (TDEP) method is generalized beyond pair interactions. The second- and third-order force constants are determined consistently from <em>ab initio</em> molecular dynamics simulations at finite temperature. The reliability of the approach is demonstrated by calculations of the mode Grüneisen parameters for Si. We show that the extension of TDEP to a higher order allows for an efficient calculation of the phonon life time, in Si as well as in <em>ε</em>-FeSi; a system that exhibits anomalous softening with temperature.</p>","","","","","","","","","","","","","2013-10-25","2013-10-25","2013-10-29","http://liu.diva-portal.org/smash/get/diva2:659443/FULLTEXT01.pdf","","2","","2","","","","","","false","","","" "655270","Lind, Hans [hanli61] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Tasnadi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (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])","Systematic theoretical search for alloys with increased thermal stability for advanced hard coatings applications","Artikel i tidskrift","Refereegranskat","eng","New Journal of Physics","1367-2630","published","15","","","","","2013","","","","Institute of Physics: Open Access Journals / Institute of Physics (IoP) and Deutsche Physikalische Gesellschaft","","","","","","10.1088/1367-2630/15/9/095010","000324462800002","","","urn:nbn:se:liu:diva-98663","","","","Teknik och teknologier (2)","","","<p>Funding Agencies|Swedish Foundation for Strategic Research (SSF)||SRL|10-0026|Swedish Research Council|621-2011-4426|</p>","<p>State-of-the-art alloys for hard coating applications, such as TiAlN, are known to suffer from decreased hardness during heat treatment in excess of 900 °C due to the formation of detrimental wurtzite AlN phases. Recent research has shown that multicomponent alloying with additional transition metals (TMs) such as Cr can shift the onset of the phase transformations to higher temperatures, but a search for new alloys is generally time-consuming due to the large number of processes that influence material properties along with the large number of alloy compositions that have to be synthesized. To overcome this difficulty we carry out systematic first-principles calculations aimed at finding potential new multicomponent TM aluminum nitride alloys for advanced hard coating applications. We direct our search towards a specific property, the thermal stability of the coating. In particular, we concentrate on the thermodynamic stability of the cubic B1 TM–Al–N phase relative to the wurtzite phase, and choose the enthalpy difference between them as our search descriptor. We perform <em>ab initio</em> calculations for all TMs, considered as impurities in AlN, and identify the most promising candidates that may improve the thermal stability. We present arguments that these elements should be targeted in future in-depth studies, theoretical, as well as experimental.</p>","","","","","","","","","","","","","2013-10-10","2013-10-10","2015-03-16","http://liu.diva-portal.org/smash/get/diva2:655270/FULLTEXT01.pdf","","3","","1","urn:nbn:se:liu:diva-115405","","","","","false","true","","" "612359","Norrby, Niklas [nikno32] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska högskolan [1751]);Lind, Hans [hanli61] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Parakhonskiy, G (University of Bayreuth, Germany );Johansson, M P. [matjo02] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska högskolan [1751]);Tasnadi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Dubrovinsky, L S. (University of Bayreuth, Germany );Dubrovinskaia, N (University of Bayreuth, Germany );Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Odén, Magnus [magod41] [0000-0002-2286-5588] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Nanostrukturerade material [2221]) (Linköpings universitet [276], Tekniska högskolan [1751])","High pressure and high temperature stabilization of cubic AlN in Ti_0.60Al_0.40N","Artikel i tidskrift","Refereegranskat","eng","Journal of Applied Physics","0021-8979","published","113","5","","","","2013","","","","American Institute of Physics (AIP)","","","","","","10.1063/1.4790800","000314746200028","","","urn:nbn:se:liu:diva-90201","","","","Teknik och teknologier (2)","","","<p>Funding Agencies|Swedish Foundation for Strategic Research (SSF)||German Research Foundation (DFG)|SPP 1236|</p><p>On the day of the defence day the status of this articla was <em>Manucsript</em> and title of this was <em>High pressure and high temperature behavior of Ti_0.60Al_0.40N</em>.</p>","<p>In the present work, the decomposition of unstable arc evaporated Ti_0.6Al_0.4N at elevated temperatures and quasihydrostatic pressures has been studied both experimentally and by first-principles calculations. High pressure and high temperature (HPHT) treatment of the samples was realized using the multi anvil press and diamond anvil cell techniques. The products of the HPHT treatment of Ti_0.6Al_0.4N were investigated using x-ray diffractometry and transmission electron microscopy. Complimentary calculations show that both hydrostatic pressure and high temperature stabilize the cubic phase of AlN, which is one of the decomposition products of Ti_0.6Al_0.4N. This is in agreement with the experimental results which in addition suggest that the presence of Ti in the system serves to increase the stability region of the cubic c-AlN phase. The results are industrially important as they show that Ti_0.6Al_0.4N coatings on cutting inserts do not deteriorate faster under pressure due to the cubic AlN to hexagonal AlN transformation.</p>","","","","","","","","","","","","","2013-03-21","2013-03-21","2015-06-01","http://liu.diva-portal.org/smash/get/diva2:612359/FULLTEXT01.pdf","","9","","2","urn:nbn:se:liu:diva-106507;urn:nbn:se:liu:diva-78830;urn:nbn:se:liu:diva-115405","","","","","false","","","" "612307","Ohlin, Kjell;Berggren, Karl-Fredrik [karbe79] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751])","Att se toner bortom Faradays vågor","Artikel i tidskrift","Övrig (populärvetenskap, debatt, mm)","swe","Fysikaktuellt","0283-9148","published","","1","","14","16","2013","","","","","","","","http://www.fysikersamfundet.se/Fysikaktuellt/2013_1.pdf","","","","","","urn:nbn:se:liu:diva-90180","","","","Fysik (103)","","","","","","","","","","","","","","","","","2013-03-21","2013-03-21","2013-03-27","","","2","","0","","","","","","false","","","" "618297","Hellman, Olle [olohe96] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Steneteg, Peter [petst55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (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]);Simak, Sergey [sersi78] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751])","Temperature dependent effective potential method for accurate free energy calculations of solids","Artikel i tidskrift","Refereegranskat","eng","Physical Review B. Condensed Matter and Materials Physics","1098-0121","published","87","10","","","","2013","","","","American Physical Society","","","","","","10.1103/PhysRevB.87.104111","000316665300002","","","urn:nbn:se:liu:diva-91545","","","","Teknik och teknologier (2)","","","<p>Funding Agencies|Knut &amp; Alice Wallenberg Foundation (KAW) project ""Isotopic Control for Ultimate Material Properties""||Swedish Research Council (VR)|621-2011-4426|LiLi-NFM||Swedish Foundation for Strategic Research (SSF) program|SRL10-0026|Ministry of Education and Science of the Russian Federation within the framework of Program Scientific and Scientific-Pedagogical Personnel for Innovative Russia|14.B37.21.089014.A18.21.0893|Swedish Government Strategic Research Area Grant in Materials Science||</p>","<p>We have developed a thorough and accurate method of determining anharmonic free energies, the temperature dependent effective potential technique (TDEP). It is based on ab initio molecular dynamics followed by a mapping onto a model Hamiltonian that describes the lattice dynamics. The formalism and the numerical aspects of the technique are described in detail. A number of practical examples are given, and results are presented, which confirm the usefulness of TDEP within ab initio and classical molecular dynamics frameworks. In particular, we examine from first principles the behavior of force constants upon the dynamical stabilization of the body centered phase of Zr, and show that they become more localized. We also calculate the phase diagram for ⁴He modeled with the Aziz et al. potential and obtain results which are in favorable agreement both with respect to experiment and established techniques.</p>","","","","","","","","","","","","","2013-04-26","2013-04-26","2013-04-30","http://liu.diva-portal.org/smash/get/diva2:618297/FULLTEXT01.pdf","","4","","2","","","","","","false","","","" "621665","Boström, Mathias (Royal Institute Technology, Sweden);Persson, Clas (Royal Institute Technology, Sweden);Ninham, Barry W (Australian National University, Australia);Norman, Patrick [patno81] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Beräkningsfysik [2208]) (Linköpings universitet [276], Tekniska högskolan [1751]);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])","Resonance interaction induced by metal surfaces catalyzes atom-pair breakage","Artikel i tidskrift","Refereegranskat","eng","Physical Review A. Atomic, Molecular, and Optical Physics","1050-2947","published","87","4","","","","2013","","","","American Physical Society","","","","","","10.1103/PhysRevA.87.044701","000317386600014","","","urn:nbn:se:liu:diva-92701","","","","Teknik och teknologier (2)","","","<p>Funding Agencies|VR|C048510170529001|STEM|34138-1|</p>","<p>We present the theory for retarded resonance interaction between two identical atoms at arbitrary positions near a metal surface. The dipole-dipole resonance interaction force that binds isotropically excited atom pairs together in free space may turn repulsive close to an ideal (totally reflecting) metal surface. On the other hand, close to an infinitely permeable surface it may turn more attractive. We illustrate numerically how the dipole-dipole resonance interaction between two oxygen atoms near a metal surface may provide a repulsive energy of the same order of magnitude as the ground-state binding energy of an oxygen molecule. As a complement we also present results from density-functional theory.</p>","","","","","","","","","","","","","2013-05-16","2013-05-16","2013-10-02","http://liu.diva-portal.org/smash/get/diva2:621665/FULLTEXT01.pdf","","5","","2","","","","","","false","","","" "624496","Bingham, Robert ( Rutherford Appleton Lab, England );Eliasson, Bengt (Ruhr University of Bochum, Germany );Tito Mendonca, Jose (Institute Super Tecn, Portugal );Stenflo, Lennart [lenst65] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751])","Ion acceleration by Alfven waves on auroral field lines","Artikel i tidskrift","Refereegranskat","eng","Physica Scripta","0031-8949","published","87","5","","","","2013","","","","Institute of Physics","","","","","","10.1088/0031-8949/87/05/058201","000318274400032","","","urn:nbn:se:liu:diva-93389","","","","Teknik och teknologier (2)","","","","<p>Observations of ion acceleration along auroral field lines at the boundary of the plasma sheet and tail lobe of the Earth show that the energy of the ions increases with decreasing density. The observations can be explained by ion acceleration through Landau resonance with kinetic Alfven waves (KAWs) such that k(A) . v(i) = omega(A), where k(A) is the wave vector, v(i) is the ion resonance velocity and omega(A) is the Alfven wave frequency. The ion resonance velocities are proportional to the Alfven velocity which increases with decreasing density. This is in agreement with the data if the process is occurring at the plasma sheet tail lobe boundary. A quasi-linear theory of ion acceleration by KAWs is presented. These ions propagate both down towards and away from the Earth. The paths of the Freja and Polar satellites indicate that the acceleration takes place between the two satellites, between 1Re and 5Re. The downward propagating ions develop a horseshoe-type of distribution which has a positive slope in the perpendicular direction. This type of distribution can produce intense lower hybrid wave activity, which is also observed. Finally, the filamentation of shear Alfven waves is considered. It may be responsible for large-scale density striations.</p>","","","","","","","","","","","","","2013-05-31","2013-05-31","2013-05-31","","","4","","1","","","","","","false","","","" "535785","Glazyrin, K. (Bayerisches Geoinstitut, Universität Bayreuth, Germany);Pourovskii, L. (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282]) (Linköpings universitet [276], Tekniska högskolan [1751]);Dubrovinsky, L. (Bayerisches Geoinstitut, Universität Bayreuth, Germany);Narygina, O. (School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK);McCammon, C. (Bayerisches Geoinstitut, Universität Bayreuth, Germany);Hewener, B. (Technische Universität Kaiserslautern, Kaiserslautern, Germany);Schünemann, V. (Technische Universität Kaiserslautern, Kaiserslautern, Germany);Wolny, J. (Technische Universität Kaiserslautern, Kaiserslautern, Germany);Muffler, K. (Technische Universität Kaiserslautern, Kaiserslautern, Germany);Chumakov, A. I. (ESRF, Grenoble Cedex, France);Crichton, W. (ESRF, Grenoble Cedex, France);Hanfland, M. (ESRF, Grenoble Cedex, France);Prakapenka, V. (GeoSoilEnviroCARS, University of Chicago, Argonne National Laboratory, USA);Tasnádi, Ferenc [ferta55] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Ekholm, Marcus [marek10] [0000-0002-7563-1494] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Aichhorn, M. (Centro Atómico Constituyentes, GIyANN, CNEA, San Martin, Buenos Aires, Comisión Nacional de Investigaciones Científicas y Técnicas, Ciudad de Buenos Aires, Argentina);Vildosola, V. (Centro Atómico Constituyentes, GIyANN, CNEA, San Martin, Buenos Aires, Comisión Nacional de Investigaciones Científicas y Técnicas, Ciudad de Buenos Aires, Argentina);Ruban, A. V. (12Department of Materials Science and Engineering, Royal Institute of Technology, Stockholm, Sweden);Katsnelson, M. I. (Radboud University Nijmegen, Institute for Molecules and Materials, Netherlands);Abrikosov, Igor [igoab43] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751])","Importance of correlation effects in hcp iron revealed by a pressure-induced electronic topological transition","Artikel i tidskrift","Refereegranskat","eng","Physical Review Letters","0031-9007","published","110","11","","","","2013","","","","American Physical Society","","","","","","10.1103/PhysRevLett.110.117206","000316172500027","","","urn:nbn:se:liu:diva-78777","","","","Teknik och teknologier (2)","","","<p>Funding Agencies|Swedish e-Science Research Centre (SeRC)||Swedish Research Council|621-2011-4426|Swedish Foundation for Strategic Research (SSF) programs SRL Grant|10-0026|German Science Foundation (DFG)||German Ministry for Education and Research (BMBF)||National Science Foundation-Earth Sciences|EAR-1128799|Department of Energy-Geosciences|DE-FG02-94ER14466|U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences|DE-AC02-06CH11357|</p>","<p>We discover that hcp phases of Fe and Fe0.9Ni0.1 undergo an electronic topological transition at pressures of about 40 GPa. This topological change of the Fermi surface manifests itself through anomalous behavior of the Debye sound velocity, c/a lattice parameter ratio, and Mossbauer center shift observed in our experiments. First-principles simulations within the dynamic mean field approach demonstrate that the transition is induced by many-electron effects. It is absent in one-electron calculations and represents a clear signature of correlation effects in hcp Fe. DOI: 10.1103/PhysRevLett.110.117206</p>","","","","","","","","","","","","","2012-06-20","2012-06-20","2015-08-19","","","20","","2","urn:nbn:se:liu:diva-78781","","","","","true","","","" "608240","Alling, Björn [bjoal69] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Tunnfilmsfysik [2232]) (Linköpings universitet [276], Tekniska högskolan [1751]);Hultberg, L (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (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])","Strong electron correlations stabilize paramagnetic cubic Cr1-xAlxN solid solutions","Artikel i tidskrift","Refereegranskat","eng","Applied Physics Letters","0003-6951","published","102","3","","","","2013","","","","American Institute of Physics (AIP)","","","","","","10.1063/1.4788747","000314032600038","","","urn:nbn:se:liu:diva-89520","","","","Teknik och teknologier (2)","","","<p>Funding Agencies|Swedish Research Council (VR) Grant|621-2011-4417621-2010-3927621-2011-4426|European Research Council|227754|Swedish Foundation for Strategic Research (SSF) strategic Research Center MS2E|A3 05:192SRL10-0026|</p>","<p>The stability of rock salt structure cubic Cr1-xAlxN solid solutions at high Al content and high temperature has made it one of the most important materials systems for protective coating applications. We show that the strong electron correlations in a material with dynamic magnetic disorder is the underlying reason for the observed stability against isostructural decomposition. This is done by using the first-principles disordered local moments molecular dynamics technique, which allows us to simultaneously consider electronic, magnetic, and vibrational degrees of freedom.</p>","","","","","","","","","","","","","2013-02-26","2013-02-26","2016-08-31","http://liu.diva-portal.org/smash/get/diva2:608240/FULLTEXT01.pdf","","4","","2","","","","","","false","","","" "686642","Brodin, Gert (Umeå University, Umeå, Sweden);Stenflo, Lennart [lenst65] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751])","Stimulated Brillouin scattering in magnetized plasmas","Artikel i tidskrift","Refereegranskat","eng","Journal of Plasma Physics","0022-3778","published","79","6","","983","986","2013","","","","Cambridge University Press","","","","","","10.1017/S0022377813000664","000330469800002","","","urn:nbn:se:liu:diva-103069","","","","Naturvetenskap (1)","","","","<p>Previous theory for stimulated Brillouin scattering is reconsidered and generalized. We introduce an effective ion sound velocity that turns out to be useful in describing scattering instabilities.</p>","","","","","","","","","","","","","2014-01-13","2014-01-13","2014-02-28","http://liu.diva-portal.org/smash/get/diva2:686642/FULLTEXT01.pdf","","2","","1","","","","","","false","","","" "681164","Zhang, Wenmin ( Zhejiang University, Peoples R China );Yu, M Y (Zhejiang University, Peoples R China );Karimov, A R (Russian Academic Science, Russia );Stenflo, Lennart [lenst65] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751])","Intense oscillations in the expansion of an inhomogeneous cylindrical electron-positron layer","Artikel i tidskrift","Refereegranskat","eng","Physica Scripta","0031-8949","published","88","5","","055501","","2013","","","","Institute of Physics","","","","","","10.1088/0031-8949/88/05/055501","000327584700011","","","urn:nbn:se:liu:diva-102719","","","","Teknik och teknologier (2)","","","<p>Funding Agencies|National Natural Science Foundation of China|113742621120519411247007|Open Fund of the State Key Laboratory of High Field Laser Physics||Shanghai Institute of Optics and Fine Mechanics||Ministry of Science and Technology of China|2011GB105000|Energy and Propulsion Systems LLC||</p>","<p>Large amplitude oscillations in the expansion of a cylindrical electron-positron plasma layer are investigated. The cold fluid equations and the Poissons equation are solved non-perturbatively in order to allow for very large amplitude oscillations. It is found that oscillations are self-excited during the expansion and can grow to very large amplitudes as the expansion slows down with time and the plasma density decreases. The kinetic energy of the expansion is thereby converted into that of the oscillations.</p>","","","","","","","","","","","","","2013-12-19","2013-12-19","2013-12-19","","","4","","1","","","","","","false","","","" "686645","Eliasson, B (University of Strathclyde, Glasgow, UK);Stenflo, Lennart [lenst65] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751]);Bingham, R (Rutherford Appleton Laboratory, Didcot, UK);Mendonca, J T (Institute Superior Tecnico, Lisboa, Portugal)","Preface to special issue","Artikel i tidskrift","Övrigt vetenskapligt","eng","Journal of Plasma Physics","0022-3778","published","79","6","","981","981","2013","","","","Cambridge University Press","","","","","","10.1017/S0022377813001426","","","","urn:nbn:se:liu:diva-103070","","","","Naturvetenskap (1)","","","","<p>This special issue is devoted to the memory of Professor Padma Kant Shukla, who passed away 26 January 2013 on his travel to New Delhi, India to receive the prestigious Hind Rattan (Jewel of India) award. Padma was born in Tulapur, Uttar Pradesh, India, 7 July 1950, where he grew up and got his education. He received a PhD degree in Physics at the Banaras Hindu University, Varanasi, Uttar Pradesh, India, in 1972, under the supervision of late Prof. R. N. Singh, and a second PhD degree in Theoretical Plasma Physics from Umeå University in Sweden in 1975, under the supervision of Prof. Lennart Stenflo. He worked at the Faculty of Physics &amp; Astronomy, Ruhr-University Bochum, Germany since January 1973, where he was a permanent faculty member and Professor of International Affairs, a position that was created for him to honour his international accomplishments and reputation.</p>","","","","","","","","","","","","","2014-01-13","2014-01-13","2014-01-13","","","4","","1","","editorialMaterial","","","","false","","","" "686648","Karimov, A R (Russian Academy of Sciences, Moscow, Russia);Yu, M Y (Zhejiang University, Hangzhou, China );Stenflo, Lennart [lenst65] (Linköpings universitet [276], Institutionen för fysik, kemi och biologi [282], Teoretisk Fysik [2229]) (Linköpings universitet [276], Tekniska högskolan [1751])","Asymmetric oscillatory expansion of a cylindrical plasma","Artikel i tidskrift","Refereegranskat","eng","Journal of Plasma Physics","0022-3778","published","79","6","","1007","1009","2013","","","","Cambridge University Press","","","","","","10.1017/S0022377813000901","000330469800008","","","urn:nbn:se:liu:diva-103071","","","","Naturvetenskap (1)","","","","<p>Asymmetric oscillatory expansion of a cylindrical plasma layer into vacuum is investigated analytically by solving the fluid equations of the electrons and ions together with the Maxwell's equations. For the problem considered, it is found that the asymmetrical flow components are strongly affected by the symmetrical components, but not the vice versa.</p>","","","","","","","","","","","","","2014-01-13","2014-01-13","2014-02-28","http://liu.diva-portal.org/smash/get/diva2:686648/FULLTEXT01.pdf","","3","","1","","","","","","false","","",""