Atomic-Scale Evolution of Local Electronic Structure Across Multiferroic Domain Walls



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Direct evidence of the electronic config­urations across domain walls in BiFeO3 is quantitatively characterized by cross-sectional scanning tunneling microscopy. Atomic-scale band evolution and the asymmetrically built-in potential barrier at domain boundaries are demonstrated. The 109° domain walls register a remarkable decrease in the bandgap, suggesting a new route to control the local conducting channels within 2 nm.