First principle investigation of phase transition and thermodynamic properties of SiC

First principle calculations are employed to investigate the phase transition and thermodynamic properties of cubic silicon carbide. The Perdew-Burke-Ernzerhof (PBE) and the Perdew-Burke-Ernzerh of for solids (PBEsol) generalized gradient approximation (GGA) are used as the exchange-correlation potential respectively to reproduce the phase transition from zinc-blende (ZB) structure to rock-salt (RS) structure of silicon carbide. Then, they are compared with previous results and experiments which are calculated with different pseudopotentials. Both of the two pseudopotentials show reasonable results on equilibrium properties of SiC. However, Further analysis show that the calculated lattice constants, bulk modulus and elastic constants with PBEsol are indeed better than the calculations with PBE, while the PBEsol pseudopotentials has a lower evaluation than the PBE and other pseudopotentials on calculating the phase transition pressure of cubic silicon carbide. Moreover, the thermodynamic properties are studied with the quasi-harmonic Debye model. The isothermal bulk modulus and the adiabatic bulk modulus, the specific heat at constant volume and pressure, the Debye temperature and the entropy under different pressures and temperatures have been successfully obtained and discussed in detail. (C) 2015 Elsevier B.V. All rights reserved.