%0 Journal Article
%K Electric fields
%K density functional theory
%K Domain walls
%K Ferroelectric materials
%K ferroelectricity
%K Degrees of freedom (mechanics)
%K Metal insulator transition
%K Transition metals
%K Transition metal compounds
%K Domain wall orientations
%K Environmental friendliness
%K External electric field
%K Insulator metal transition
%K Phenomenological theory
%K Strong electronic correlations
%K Tail-to-tail domain walls
%K Transition-metal oxides
%A D Meier
%A J Seidel
%A A Cano
%A K Delaney
%A Y Kumagai
%A M Mostovoy
%A N.A Spaldin
%A Ramamoorthy Ramesh
%A M Fiebig
%B Nature Materials
%D 2012
%G eng
%I Nature Publishing Group
%P 284-288
%R 10.1038/nmat3249
%T Anisotropic conductance at improper ferroelectric domain walls
%V 11
%X 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 ErMnO3 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 ErMnO3 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. © 2012 Macmillan Publishers Limited. All rights reserved.