Phase transition and thermodynamic properties of TiN under pressure via first-principles calculations

Abstract

The phase transition of TiN from the NaCl structure to the CsCl structure is investigated by the first-principles plane wave pseudopotential density functional theory method, and the thermodynamic properties of the NaCl structures are obtained through the quasi-harmonic Debye model. It is found that the pressures for transition from the NaCl structure to the CsCl structure are 364.1 GPa (for GGA) and 322.2 (for LDA) from equal enthalpies. The calculated ground state properties such as equilibrium lattice constant, bulk modulus, and its pressure derivative are in good agreement with experimental and theoretical data of others. Moreover, the dependences of the relative volume V/V0 on the pressure P, the Debye temperature ΘD, and heat capacity CV on the pressure P and temperature T, as well as the variation of the thermal expansion α with temperature and pressure are also successfully obtained.