First-principles study of phase transition and thermodynamic properties of InP

Using first-principles calculations, the structural phase transition between the zinc-blende (ZB) and the rocksalt (RS) phases and the thermodynamic properties of indium phosphide (InP) are investigated by means of the pseudo-potential plane-waves method. The calculations are performed within the generalized gradient approximation (GGA) to density functional theory with the Perdew-Burke and Ernzerhof (PBE) exchange-correlation functional. On the basis of the third-order Birch–Murnaghan equation of states, the transition pressure Pt=10 GPa between the ZB and RS phases of InP is determined. The calculated values are in excellent agreement with experiments and similar theoretical calculations. From the theoretical calculations, the relationship of the relative volume V/V0, the Debye temperature Θ and the heat capacity CV with the pressure P and temperature T is also successfully obtained.