抄録
Ferroelectric materials are used as sensors, actuators, memory devices, optical devices and so on. Their properties are influenced by polarization direction and domain walls. It is thus important to understand the atomic structure and formation process of domain walls in ferroelectric materials. In this study, first-principles calculations were performed for LiNbO_3 to investigate the electronic and atomic structures of the domain walls. The calculations showed that the excess energy of (1120) domain wall was 170mJ/m^2, while the average of two (1100) domain walls was 190mJ/m^2. It was found that the atomic structure and excess energy of a domain wall depend on the crystalline plane which is parallel to the domain wall.
