The high-pressure phase transitions and vibrational properties of zinc-blende XTe (X = Zn, Cd, Hg): Performance of local-density-approximation density functional theory

摘要

We have performed a systematical investigation on the pressure-induced phase transitions between zinc-blende and cinnabar phase for group IIB-VIA compounds: ZnTe, CdTe, and HgTe by ab initio plane-wave pseudopotential density functional theory (DFT). The calculations are performed within the local density approximation (LDA) in the scheme of Ceperley-Alder parametrized by Perdew and Zunger (CA-PZ). The obtained ground state properties and equation of state agree well with the available experimental data and calculated results. The transition pressures P_t are determined through both the analysis of enthalpy variation with pressure and the slope of the common tangent of the energy-volume curves. The linear-response approach is used to calculate the phonon dispersions, which agree well with the experiments. Finally, the thermodynamic properties such as the free energy (F), the enthalpy (H), entropy (S) and heat capacity (C_v) are obtained successfully from the phonon density of state.