Pressure-induced vibrational and electronic properties of palladium per nitride

Abstract

We predict electronic and structural phase transition at 11GPa for crystalline PdN2 in pyrite structure by employing first principles calculation using density functional theory implemented in Quantum Espresso code. The electronic band structure, equation of states and dynamical properties at zero as well as high pressure are calculated within the frame work of conventional GGA exchange correlation functional. We report the sharp change of the Pd-N and N-N bond length at phase transition pressure in support of isostructural phase transition driven by electronic phase transition for PdN2 in pyrite structure. The calculated Raman frequencies near the phase transition pressure reveals the first order isostructural phase transition by the instability of longitudinal acoustical as well as optical branches, provides the mechanism for experimentally observed decomposition below 13GPa.