BiFeO3Domain Wall Energies and Structures: A Combined Experimental and Density FunctionalTheory+UStudy

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.

Orientations of low-energy domain walls in perovskites with oxygen octahedral tilts

“…They are qualitatively consistent with the first-principles calculations and experimental measurements. 21 It should be noted that the first-principles calculations were performed at 0K, and the DW width is smaller than our values obtained at room temperature. As shown in Fig.…”

Real-Time Observation of Local Strain Effects on Nonvolatile Ferroelectric Memory Storage Mechanisms

“…Inverse fast Fourier transforms (IFFTs) formed using the (100) and (−100) reflections inside the boxed regions reveal an edge-type dislocation at the intersection of the domain and the SrTiO 3 substrate, which can add electrostatic potential and potentially lead to domain nucleation or pinning. 34 On the basis of the microstructure shown in Figures 1 and 2, three unique behaviors are analyzed by outlining and tracking three domains using frames from the in situ videos captured under an applied bias of ∼115 V/cm (Figure 3). These domains are chosen as test cases to provide a comparison for the evolution of the morphologies of each of these domains versus time, highlighting differences related to the microstructural environment surrounding the domains.…”

Switching the curl of polarization vectors by an irrotational electric field

“…Furthermore, the corner-sharing network of oxygen octahedra serves as the "skeleton" of the crystal, and the distortion of the tilt vectors costs substantial energy [18]. Due to the possibility of the polarization and tilt vectors being antiparallel and the substantial energy cost related to the tilt vectors, the domain wall energy hierarchy in BFO becomes 109° < 180° < 71°, rather than the expected 71° < 109° < 180° [17][18][19][20].…”

“…To demonstrate the formation of vortex domains under the above conditions, the 109° domain walls in the (001) p BFO films under a small epitaxial strain are studied as a model system. We choose the 109° domain walls since they have the lowest wall energy in BFO [18][19][20].…”