Elastic properties of the high-pressure rock-salt phase of ZnO

Abstract A pseudopotential and plane-wave based on the density functional theory (DFT) and carried within the exchange-correlation potential in the local density approximation (LDA) method were applied to investigate the relative stability and the elastic properties of ZnO under different hydrostatic pressures. The structural phase transition from the wurtzite to rock-salt structures and the elastic constants were all investigated. The calculated transition pressure and the elastic constants at zero pressure for the two structures are all in excellent agreement with their corresponding experimental and theoretical values. Moreover, a phase transition from rock-salt to caesium chloride structure is predicted to occur at 268 GPa according to the elastic mechanical instability. The pressure dependence of the bulk modulus, K, the shear modulus, G, the compressional wave velocity, VP , the shear wave velocity, VS , and the elastic anisotropy factor, A, for the rock-salt structure of ZnO are all successfully obtained. Acknowledgements The authors are grateful to X. Gonze et al. for providing their version of code of ABINIT. The authors would like to thank the financial support by the National Natural Science Foundation of China and China Academy of Engineering Physics under grant No. 10676025 (NSAF).