Stability of Ternary Perovskites Sc_3 EN (E=B, Al, Ga, In) from First Principles
A. S. Mikhaylushkin, C. Höglund, J. Birch, Zs. Czigány, L. Hultman, S. I. Simak, B. Alling, F. Tasnádi, and I. A. Abrikosov
Mechanical and thermodynamic stability of the isoelectronic ternary inverse perovskites Sc_3 EN (E=B,Al,Ga,In) has been studied from first principles. We confirm stability of recently synthesized cubic phases Sc_3 AlN and Sc_3 InN, and predict the stability of cubic Sc_3 GaN and a triclinic phase aP20-Sc_3 BN. Substantial phonon softening in Sc_3 AlN and Sc_3 GaN is observed indicating a possibility that structural defects could form readily. In accord, our experiments show that magnetron sputter deposited films contain regions with high density of nonperiodic stacking faults along the <111> growth direction. We suggest that defect-free crystals may exhibit anomalies in the carrier properties, promising for electronic applications.
Phonon spectra of a) Sc3BN, b) Sc3AlN, c) Sc3GaN, and d) Sc3InN. frequencies.
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Last updated: 05/12/09