Molecular dynamics simulation of thermodynamic and thermal transport properties of strontium titanate with improved potential parameters

A molecular dynamics simulation has been performed to investigate the thermal expansivity, isothermal compressibility, heat capacity and thermal conductivity of strontium titanate. The potential model captures the ionic and covalent characteristics of strontium titanate well. The parameters of the model were derived by fitting against the experimental lattice parameters. With these fitted parameters, we then evaluated the variations of lattice, thermal expansion coefficient, isothermal compressibility, heat capacity and thermal conductivity as a function of temperature from room temperature up to 2000 K, and pressure from ambient pressure up to 20.3 GPa. The thermal conductivity calculations were performed using non-equilibrium molecular dynamics method, and corrections for finite size effect were made. The simulation results are in good agreement with the experimental data and the theory.