Abstract:

First-principles theoretical study of the elastic and thermodynamic properties of ZnTe in zinc-blende (ZB) structure at high temperature and pressure was performed by using the plane-wave pseudopotential method. The calculated lattice parameter of 0.6095 nm is in excellent agreement with the experimental value of 0.6103 nm and is only 0.1% smaller. The elastic constants and bulk modulus at p =0 GPa and T =0 K are also in agreement with experimental data. From the values of the elastic constants at high pressures, the transition pressure is about 10 GPa judged by the mechanical stability conditions of cubic crystals and this is consistent with available experimental data. The Debye temperature (249 K) at the normal temperature (T=300 K) and the values for heat capacity (CV) at different pressures and temperatures were also obtained by applying the quasi-harmonic Debye model. We found that the CV decreased with the increase of pressure and was close to the Dulong-Petit limit at high temperature and pressure.

Key words: ZnTe, Elastic constant, Phase transition, Thermodynamic property, Quasi-harmonic Debye model