Transport anisotropy of LaAlO3/SrTiO3 interfaces on chemically patterned SrTiO3

A few years ago high mobility electronic transport was found at the interface between the wide bandgap insulators SrTiO3 and LaAlO3. This conductive layer is confined to a few unit cells around the interface and it appears when LaAlO3 layers with thickness above 3-4 unit cells are grown on SrTiO3. It is known that TiO2/LaO interfaces are conductive, while SrO/AlO2 interfaces are insulating. Here we exploited this way to control the interface properties to produce large scale functional nanostructures. TiO2/AlO-SrO/LaO2 modulated interfaces have been prepared using thermally treated SrTiO3 surfaces with self-organized patterned chemical termination. The interface transport properties are found to be controlled according to these interface patterns. While the influence of the interface topology, e.g. terrace steps, is negligible, a strong transport anisotropy is observed when large-scale well oriented chemical patterns are realized. Our results show that bottom-up engineering of the interface chemical composition is a suitable strategy to influence the transport properties on large scales.