Investigation of mechanical stability of possible structures of PtN using first-principles computations (original) (raw)

We report an ab initio study of the mechanical stability of platinum nitride (PtN), in four different crystal structures, the rock salt (rs-PtN), zinc blende (zb-PtN), cooperite and a face centered orthorhombic phase. Only the rs-PtN phase is found to be stable and has the highest bulk modulus B = 284 GPa. Its electronic density of states shows no band gap making it metallic. The zb-PtN phase does not stabilize or harden by the nitrogen vacancies investigated in this study. Therefore, the experimental observation of super hardness in PtN remains a puzzle.