Phase-field simulation of domain structures in epitaxial BiFeO₃ films on vicinal substrates

The ferroelectric domain structures of epitaxial BiFeO₃ thin films on miscut substrates were studied using a phase-field model. The effects of substrate vicinality towards (100) are considered by assuming charge-compensated surface and film/substrate interface. The predicted domain structures show remarkable agreement with existing experimental observations, including domain wall orientations and local topological domain configurations. The roles of elastic, electric, and gradient energies on the domain structures were analyzed. It is shown that the substrate strain anisotropy due to the miscut largely determines the domain variant selection and domain configurations.