Abstract
A first-principles-derived approach is used to investigate the temperature-versus-misfit strain phase diagram of (Ba(0.70)Sr(0.30))TiO(3) ultrathin film. Our predicted phase diagram is qualitatively similar to those developed by Shirokov et al (2009 Phys. Rev. B 79 144118) and Ban and Alpay (2002 J. Appl. Phys. 91 9288). However, there are some quantitative differences that are microscopically revealed and explained. The results also indicate that the electrical polarization is very sensitive to the applied strain. Moreover, the polarization components show a strong dependence on the surface/interface, thickness, and electrical boundary conditions.