First principles study of the thermodynamic, mechanical and electronic properties of crystalline phases of Chromium Nitrides

Abstract

We performed first principles calculations using the Density Functional Theory (DFT) method with the PBE0 hybrid functional for exchange and correlation energy, to determine the thermodynamic and mechanical properties and stability of the system Cr–N. We report formation energy, cohesive energy, lattice parameters, Wyckoff positions, elastic constants, elastic moduli and Debey temperature. For Cr 2N we also report the electronic properties through the density of states, band structure and electron charge density calculations. We found three new stable phases of Cr2N: P6‾m2, Amm2 and Immm, of which Amm2 is the most stable structure with an enthalpy of formation of −0.991 eV and with the highest values of elastic moduli. In addition, Cr2N–structures resulted harder than CrN–structures.