Quasipolaron Surface Polarization in Bismuth Ferrite

Abstract

Multiferroic BiFeO${}_{3}$ has been surprising researchers with its properties for decades now, and questions related to the origin of its polarization and the various mechanisms behind its ferroelectric properties are still important. This study shows that in BiFeO${}_{3}$, quasipolaron surface polarization is the origin of a nested domain structure. As more quasipolarons are pinned at the surface per unit area, the surface density of antiferromagnetically ordered spins increases. The large remanent polarization and superior antiferromagnetic properties show that the surface of bismuth ferrite is important for spintronics.