title: BiFeO3 domain wall energies and structures: a combined experimental and density functional theory+U study.
abstract: We determined the atomic structures and energies of 109°, 180°, and 71° domain walls in BiFeO3, combining density functional theory+U calculations and aberration-corrected transmission electron microscopy images. We find a substantial Bi sublattice shift and a rather uniform Fe sublattice across the walls. The calculated wall energies (γ) follow the sequence γ109<γ180<γ71 for the 109°, 180°, and 71° walls. We attribute the high 71° wall energy to an opposite tilting rotation of the oxygen octahedra and the low 109° wall energy to the opposite twisting rotation of the oxygen octahedra across the domain walls.
authors.affiliation: Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.forename: Chris
authors.initials: C
authors.lastname: Nelson
authors.forename: Alexander
authors.initials: A
authors.lastname: Melville
authors.forename: Benjamin
authors.initials: B
authors.lastname: Winchester
authors.forename: Shunli
authors.initials: S
authors.lastname: Shang
authors.forename: Zi-Kui
authors.initials: ZK
authors.lastname: Liu
authors.forename: Darrell G
authors.initials: DG
authors.lastname: Schlom
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Pan
authors.forename: Long-Qing
authors.initials: LQ
authors.lastname: Chen