Phase transition and thermodynamic properties of beryllium telluride under high pressure

Abstract

A theoretical investigation on structural, dynamical, phase diagram and thermodynamic properties of beryllium telluride (BeTe) under high pressure and temperature is presented in the framework of density functional theory. The calculated structural parameters of BeTe in both zinc blende (ZB) and nickel arsenide (NiAs) structures are in reasonable agreement with available experimental data and previous theoretical work. The phonon dispersion relations, dielectric tensor and Born effective charge are investigated within the density functional perturbation theory (DFPT). The investigation of the phase diagram indicated that the NiAs structure BeTe becomes stable at high pressure and temperature. Based on the quasiharmonic Debye model, the pressure and temperature dependences of bulk modulus, Grüneisen parameter, Debye temperature, specific heat and thermal expansion coefficient are all successfully obtained. We hope that the theoretical results reported here can give more insight into the structural and thermodynamic properties of other semiconductors at high temperature and pressure.