The structure and thermodynamic properties of zinc oxide with wurtzite and rocksalt structure under high pressures

The structure and thermodynamic properties with the wurtzite and rocksalt structures of ZnO under high pressures and temperatures have been investigated using pseudopotential and plane wave basis based on the density functional theory. The effects of the pressures and temperatures on the structure and thermodynamic properties such as the thermal expansion coefficient, the heat capacity and the isothermal bulk modulus are all investigated for both two structures at extended pressure and temperature ranges. It is found that the wurtzite structure phase of ZnO is with the smaller isothermal bulk modulus, the smaller thermal expansion coefficient, and the smaller constant-pressure heat capacity comparing with the rocksalt structure phase of ZnO under the same conditions. All the calculated structure and thermodynamic properties agree well with the available values reported in the literatures.