Two-dimensional simulations on the interactions of O 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 O vacancies was coupled through Maxwell's equation. The results showed that two barriers near the electrodes existed in both the 90° and 180° domain structures. It had also been observed that while an intrinsic electrostatic potential drop across the 90° domain wall created the electric fields which drove the electrons and O vacancies aggregate on the different sides of the domain wall, the 180° domain wall had insignificant interaction with the potential, and no electron or vacancy accumulation in 180° domain structure was observed. Polarization charge density was believed to be the origin of this difference.

Interaction of O Vacancies and Domain Structures in Single Crystal BaTiO3 - Two-Dimensional Ferroelectric Model. L.Hong, A.K.Soh, Q.G.Du, J.Y.Li: Physical Review B, 2008, 77[9], 094104 (7pp)