Phase diagrams and dielectric response of epitaxial (BaxSr1−x)TiO3 ultrathin films: A first-principles study

A method based on first-principles calculations was used to construct temperature versus misfit strain phase diagrams for epitaxial (BaxSr1−x)TiO3 ultrathin films over the entire composition range from x=0 to x=1. The predicated phase diagrams show “topologies” that are similar to those calculated by Shirokov et al. (Phy. Rev. B. 79 (2009) 144118), but with quantitative differences that are examined and explained. The dependence of the dielectric permittivity on the misfit strain and the film composition at room temperature are also investigated and compared with available theoretical predications and experimental measurements.