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

摘要

We carried out ab initio calculations for technologically important ABO(3) perovskites, like, CaZrO3, BaZrO3, PbTiO3 and SrTiO3, their (001), (011) and (111) surfaces as well as (001) interfaces. For ABO(3) 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.