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

We have performed ab initio calculations for the cubic inverse-perovskite Sc3EN E=Al,Ga, In systems tostudy their electronic band-structures and elastic properties. In this study, we used the accurate augmentedplane wave plus local orbital method to find the equilibrium structural parameters and to compute the fullelastic tensors. The obtained single-crystal elastic constants were used to quantify the stiffness of the Sc-basedternary 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 Sc6N cluster andthe surrounding metallic lattice of either Al, Ga, or In atoms. Our calculations show that Sc3GaN has the largestcovalent Sc-N bonding-type character with the highest Young, shear, and bulk moduli. Compared with theother two isoelectronic systems, it also behaves as the most brittle material with a relatively large elasticanisotropy