BiFeO₃中のCrystallographic shear型二次元格子欠陥のマルチフェロイクス特性に関する第一原理解析

抄録

Multiferroic properties of crystallographic shear (CS) plane in BiFeO₃ are calculated using first-principles calculations. We find that the polarization and the magnetic moment are spontaneously rotated by 109 degrees through CS plane, while those in BiFeO₃ bulk are uniform. The rotation of the polarization shows the transition involving its continuous rotation and discontinuous head-to-head type reversal, which is generally unstable in perfect crystal. These multiferroic properties are caused by edge-sharing of oxygen octahedra and localization of hole which emerges by nonstoichiometry of CS plane.