Dynamical Insights into Oxygen Diffusion in BaTiO3 and SrTiO3

Oxygen diffusion is a key process in BaTiO3 and SrTiO3 that determines many of their important electronic properties. Despite the importance of oxygen diffusion in these systems, there is still currently significant variation in the oxygen diffusion coefficients for BaTiO3 and SrTiO3 reported in the literature from both experimental and computational methods. Using molecular dynamics simulations, the effect of oxygen vacancy concentration on the oxygen diffusion properties is investigated for these perovskite materials. Oxygen diffusion coefficients and activation energies for both materials are calculated over a temperature range of 900-1500 K. Oxygen vacancy charge compensation is achieved by the reduction of Ti4+ to Ti3+ ions, in agreement with experimental results for undoped BaTiO3 and SrTiO3. The findings from this study yield an accurate reference point for the calculation of oxygen diffusion in these materials and also the application of molecular dynamics in studying such phenomena.