Interplay between Ca- and Ti-driven ferroelectric distortions in (Ba, Ca)TiO3 solid solutions from first-principles calculations

摘要: (Ba,Ca)(Ti,Zr)O3 solid solutions are promising lead-free piezoelectrics near their polymorphic phase boundary, which is believed to be linked the interplay between B-site driven ferroelectricity and A-site ferroelectricity. Focusing on (Ba,Ca)TiO3, we support this picture from first-principles calculations. In particular, show how steric effects related partial substitution of Ba by Ca largely enhance Ca-driven ferroelectricity, already virtually allowed in parent CaTiO3. The emergent Ti-driven mechanisms lowers energy barrier different polar states, eventually results a quasi-isotropic polarization under small concentration Ca. A sizeable enhancement piezoelectric response directly these features.(Ba,Ca)(Ti,Zr)O3 features.