Elastic properties and electrostructural correlations in ternary scandium-based cubic inverse perovskites: A first-principles study

Abstract

We have performed ab initio calculations for the cubic inverse-perovskite Sc3 EN (E=Al,Ga,In) systems to study their electronic band-structures and elastic properties. In this study, we used the accurate augmented plane wave plus local orbital method to find the equilibrium structural parameters and to compute the full elastic tensors. The obtained single-crystal elastic constants were used to quantify the stiffness of the Sc-based ternary nitrides and to appraise their mechanical stability. The site-projected density of states, Fermi surfaces, and the charge-density plots have also been used to analyze the chemical bonding between the Sc6 N cluster and the surrounding metallic lattice of either Al, Ga, or In atoms. Our calculations show that Sc3 GaN has the largest covalent Sc-N bonding-type character with the highest Young, shear, and bulk moduli. Compared with the other two isoelectronic systems, it also behaves as the most brittle material with a relatively large elastic anisotropy. © 2009 The American Physical Society.