Elastic properties of antiperovskite-type Ni-rich nitrides MNNi3 (M=Zn, Cd, Mg, Al, Ga, In, Sn, Sb, Pd, Cu, Ag and Pt) as predicted from first-principles calculations

We have performed accurate ab initio total energy calculations using the full-potential linearized augmented plane wave (FP-LAPW) method with the generalized gradient approximation (GGA) for the exchange-correlation potential to systematically investigate elastic properties of 12 synthesized and hypothetical cubic antiperovskite-type Ni-rich nitrides MNNi3, where M are Zn, Cd, Mg, Al, Ga, In, Sn, Sb, Pd, Cu, Ag and Pt. As a result, the optimized lattice parameters, independent elastic constants (Cij), bulk-, shear- and tetragonal shear moduli, Cauchy’s pressure and some indexes of elastic anisotropy, as well as the numerical estimations of Young’s modulus, Poisson’s ratio and Pugh's indicator of brittle/ductile behavior for the corresponding polycrystalline MNNi3 (in the Voigt-Reuss-Hill approximation) were obtained and analyzed in comparison with the available theoretical and experimental data.