Predicted the structural diversity and electronic properties of Pt−N compounds under high pressure

Abstract The nitrogen-rich transition metal nitrides have attracted considerable attention due to their potential application as high energy density materials. Here, a systematic theoretical study of PtN x compounds has been performed by combining first-principles calculations and particle swarm-optimized structure search method at high pressure. The results indicate that several unconventional stoichiometries of PtN 2 , PtN 4 , PtN 5 , and Pt 3 N 4 compounds are stabilized at moderate pressure of 50 GPa. Moreover, some of these structures are dynamically stable even when the pressure release to ambient pressure. The P 1 ˉ phase of PtN 4 and the P 1 ˉ phase of PtN 5 can release about 1.23 kJ g −1 and 1.71 kJ g −1 , respectively, upon the decomposition into elemental Pt and N 2 . The electronic structure analysis shows that all crystal structures are indirect band gap semiconductors, except for the metallic Pt 3 N 4 with Pc phase, and the metallic Pt 3 N 4 is a superconductor with estimated critical temperature T c values of 3.6 K at 50 GPa. These findings not only enrich the understanding of transition metal platinum nitrides, but also provide valuable insights for the experimental exploration of multifunctional polynitrogen compounds.