Frictional drag between graphene and LaAlO3/SrTiO3 heterostructures*

Vertical stacking of heterostructures that combine layered materials offer new ways of combining interesting properties of dissimilar electronic materials. Over the past few years we have been integrating graphene with complex-oxide heterostructures, specifically, the LaAlO₃/SrTiO₃ system. Furthermore, conducting nanostructures can be written under graphene, producing interesting interactions between the two systems. Here we report Coulomb drag measurements between single-layer graphene and a conductive LaAlO₃/SrTiO₃ interface. Fabry-Perot oscillations are observed in both graphene and drag signal in graphene, which indicate the local doping in graphene by conductive atomic force microscope(c-AFM) lithography. While the drag resistance is greatly enhanced in SrTiO₃ in the superconducting region, the drag in graphene remain unchanged. We also observed key differences between longitudinal drag and hall drag in both graphene and SrTiO₃ .