A first-principles study on the structural, elastic and electronic properties of AlCSc3 and AlNSc3

We present an ab initio study of the structural, elastic and electronic properties of the antiperovskite compounds AlCSc3 and AlNSc3. The calculated lattice parameters and equilibrium volumes are in good agreement with the available experimental data. Single-crystal elastic constants were calculated and the polycrystalline elastic moduli were estimated according to Voigt, Reuss and Hill’s approximations. The band structure shows a metallic character of both compounds; strong hybridization between Sc d–C p (or N p) and Sc d–Al p states was observed from the partial density of states. A significant charge transfer from Al to C (or N) atoms was observed. Moreover, these compounds are bonded by a mixture of ionic–covalent bonding.