Study of the thermodynamic properties of SrTiO3 perovskite under pressure by the statistical moment method with the improved interatomic potential

Abstract

The pressure dependence of the thermodynamic quantities of cubic SrTiO3 perovskite has been going based on the statistical moment method. We obtain analytic formulas of free energy, lattice parameter, thermal lattice expansion coefficient, heat capacity Cv, and Cp at various pressure. The potential with the partial charge model and functions of Demontis and Pedone is used, it allows calculating the numerical thermodynamic quantities of SrTiO3 at specific pressure and temperature. The numerical quantities of SrTiO3 have been calculated up to 18 GPa and agreed well with the previous experimental and theoretical results. It has a good potential to develop the statistical moment method for investigating the pressure effects on the thermodynamic quantities of the perovskite–structure materials.