Domain Wall Motion in Perovskite Ferroelectrics Studied by the Nudged Elastic Band Method

Because of its unique physical properties, domain wall (DW) in ferroelectrics not only plays a key role in the electrical properties of ferroelectric film but also has shown tremendous prospect in the DW-based memory and logic devices. However, the motion mechanism of ferroelectric DW, which is of great significance for the application of ferroelectric films, has not been clearly understood. In this paper, the 180° DW motions in BaTiO3 (BTO) and PbTiO3 (PTO) were studied by using the nudged elastic band method based on the density functional theory. The evolutions of atomic structure, local polarization, and energy of the system for the DW motion process between the two adjacent equilibrium positions were systematically revealed. The DW migration across the oxygen vacancy was also simulated, and the corresponding potential well for the DW motion was obtained. It was also found that the DW motion barrier could be significantly influenced by the in-plane strain. The “activation field” deduced from the energ...