Interaction of O vacancies and domain structures in single crystal BaTiO3:: Two-dimensional ferroelectric model

Two- dimensional simulations on the interactions of oxygen vacancies and different domain structures in barium titanate single crystal were carried out using the phase field method. The evolution of the spontaneous polarizations and oxygen vacancies was coupled through Maxwell's equation. The results showed that two barriers near the electrodes existed in both the 90 degrees and 180 degrees domain structures. It has also been observed that while an intrinsic electrostatic potential drop across the 90 degrees domain wall created the electric fields which drove the electrons and oxygen vacancies aggregate on the different sides of the domain wall, the 180 degrees domain wall had insignificant interaction with the potential, and no electron or vacancy accumulation in 180 degrees domain structure was observed. Polarization charge density is believed to be the origin of this difference.