Artificial tailoring of MI transition at LAO/STO interface with SrSnO3 buffer layer

Buffer layers, capping layers, gate voltage, etc., can all have a major impact on the interface conducting properties of oxide heterostructures; in some cases, the thickness of a layer significantly alters the transport properties. Here, we report the impact of the SrSnO3 buffer layer of different thicknesses at the LAO/STO interface. The metallic behavior is observed in heterostructures with a buffer layer thickness smaller than 4 uc and the interface becomes insulating for thickness >= 4 uc. XPS results showed that the oxidation state of the Sn atom had changed in the insulating samples.