FIRST-PRINCIPLE INVESTIGATION OF ELECTRIC STRUCTURES AND THERMODYNAMIC PROPERTIES FOR ZIRCONIUM NITRIDE UNDER HIGH PRESSURE

In the frame of density functional theory, first-principles calculations have been carried out to investigate the structures, elastic constants, structural phase transition between B1 and B2 phases and thermodynamic properties of the zirconium nitride (ZrN) by means of the generalized gradient approximation. The equilibrium lattice parameter we obtained for ZrN in B1 phase is closer to the experiment results than previous theoretical results. In addition, the calculations of the elastic constants show that ZrN is a brittle material. What is more, based on third-order natural strain equation of state, the phase transition pressure 338 GPa for ZrN is predicted for B1–B2 transition. According to the quasi-harmonic Debye model, the thermodynamic parameters of ZrN have been investigated systematically.