Finite-temperature properties of (Ba,Sr)TiO3 systems from atomistic simulations

An effective Hamiltonian approach is developed to mimic finite-temperature properties of (BaxSr1-x)TiO3 perovskite systems. It is found that this atomistic approach is overall quite accurate to qualitatively and quantitatively reproduce the experimental composition-temperature phase diagram of the disordered solid solutions (especially, for compositions x larger than 25%), when allowing one single parameter to deviate from its first-principles-derived value. Interestingly, such approach also yields predictions that are in good agreement with direct first-principles calculations for BaTiO3/SrTiO3 superlattices. The proposed approach is thus promising to investigate phenomena in any perovskite system made of Ba, Sr, Ti, and O atoms, independently of the overall composition and atomic arrangement.