Ab initio calculations of CaZrO₃, BaZrO₃, PbTiO₃ and SrTiO₃ (001), (011) and (111) surfaces as well as their (001) interfaces

We carried out ab initio calculations for technologically important ABO₃ perovskites, like, CaZrO₃, BaZrO₃, PbTiO₃ and SrTiO₃, their (001), (011) and (111) surfaces as well as (001) interfaces. For ABO₃ perovskites, such as CaZrO₃, BaZrO₃, PbTiO₃ and SrTiO₃, in most of cases, all upper (001) surface layer atoms relax inwards, all second surface layer atoms relax outwards, and again, all third surface layer atoms relax inwards. Our calculated CaZrO₃, BaZrO₃, PbTiO₃ and SrTiO₃ (001) surface energies are almost equivalent for both AO and BO₂-terminations, and always considerably smaller than the (011) and especially (111) surface energies. Our calculated BaTiO₃/SrTiO₃, SrZrO₃/PbZrO₃ and PbTiO₃/SrTiO₃ (001) heterostructure band gap depends much more strongly from the termination of the upper augmented layer (AO or BO₂) than from the number on the substrate augmented layers.