title: Anisotropic conductance at improper ferroelectric domain walls.
abstract: Transition metal oxides hold great potential for the development of new device paradigms because of the field-tunable functionalities driven by their strong electronic correlations, combined with their earth abundance and environmental friendliness. Recently, the interfaces between transition-metal oxides have revealed striking phenomena, such as insulator-metal transitions, magnetism, magnetoresistance and superconductivity. Such oxide interfaces are usually produced by sophisticated layer-by-layer growth techniques, which can yield high-quality, epitaxial interfaces with almost monolayer control of atomic positions. The resulting interfaces, however, are fixed in space by the arrangement of the atoms. Here we demonstrate a route to overcoming this geometric limitation. We show that the electrical conductance at the interfacial ferroelectric domain walls in hexagonal ErMnO(3) is a continuous function of the domain wall orientation, with a range of an order of magnitude. We explain the observed behaviour using first-principles density functional and phenomenological theories, and relate it to the unexpected stability of head-to-head and tail-to-tail domain walls in ErMnO(3) and related hexagonal manganites. As the domain wall orientation in ferroelectrics is tunable using modest external electric fields, our finding opens a degree of freedom that is not accessible to spatially fixed interfaces.
authors.forename: D
authors.initials: D
authors.lastname: Meier
authors.forename: J
authors.initials: J
authors.lastname: Seidel
authors.forename: A
authors.initials: A
authors.lastname: Cano
authors.forename: K
authors.initials: K
authors.lastname: Delaney
authors.forename: Y
authors.initials: Y
authors.lastname: Kumagai
authors.forename: M
authors.initials: M
authors.lastname: Mostovoy
authors.forename: N A
authors.initials: NA
authors.lastname: Spaldin
authors.forename: R
authors.initials: R
authors.lastname: Ramesh
authors.forename: M
authors.initials: M
authors.lastname: Fiebig