Phase transition properties of SmTe under pressure

Abstract

Phase transition properties of SmTe under high pressure have been investigated through ab initio pseudo-potential calculations within the framework of density functional theory. Local density approximation based on exchange-correlation energy optimization has been used for calculating the total energy of the system. The calculated equilibrium lattice constant, bulk modulus and its pressure derivative agree well with the experimental data. The first-principles studies of isostructural valence transition from Sm2+ to Sm3+ in B1 phase () and from B1 → B2 phase transition characterized by the space group in bulk SmTe have been carried out. The calculated transition pressure, equation of state and volume collapse show good agreement with experimental results. Under ambient conditions, the energy of Sm2+ in B1 phase is found to be lower than that of Sm3+. At high pressures beyond B1 → B2 phase transition, the energy of B2 phase is found to be slightly lower than that in B1 phase.