Article

Conduction at Domain Walls in Oxide Multiferroics

Department of Physics, University of California, Berkeley, 94720 California, USA.
Nature Materials (Impact Factor: 36.5). 02/2009; 8(3):229-34. DOI: 10.1038/nmat2373
Source: PubMed

ABSTRACT

Domain walls may play an important role in future electronic devices, given their small size as well as the fact that their location can be controlled. Here, we report the observation of room-temperature electronic conductivity at ferroelectric domain walls in the insulating multiferroic BiFeO(3). The origin and nature of the observed conductivity are probed using a combination of conductive atomic force microscopy, high-resolution transmission electron microscopy and first-principles density functional computations. Our analyses indicate that the conductivity correlates with structurally driven changes in both the electrostatic potential and the local electronic structure, which shows a decrease in the bandgap at the domain wall. Additionally, we demonstrate the potential for device applications of such conducting nanoscale features.

    • "Recent developments for functional twin boundaries are summarized by Salje (2010, 2012) and Salje and Zhang (2009); the possibility of using mobile magnetic boundaries as functional elements in memory devices was first proposed in racetrack technology by Stuart Parkin (2008a,b). Other crucial developments are the discovery of highly conducting boundaries by Jan Seidel and collaborators (Seidel et al., 2009, 2010) and superconducting twin walls by Aird and Salje (1998, 2000). Ferroelectric twin walls in ferroelastic CaTiO 3 were predicted by Goncalves-Ferreira et al. (2008, 2010) and the chemical enrichment of the twin walls by Calleja et al. (2003). "
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    • "Topological defects are widespread in condensed matter physics, and interactions among topological defects and the resulting configurations of numerous topological defects can be associated with various intriguing phenomena123 because they are insensitive to continuous deformation or perturbation. Topological defects in hexagonal RMnO3 (R = Ho to Lu, Y, and Sc), domain walls/vortices, are responsible for their multiferroicity which is characterized by the coexistence of multi-ferroic orders. "
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