Modulation of conductance and superconductivity by top-gating in LaAlO3/SrTiO3 2-dimensional electron systems

We report the electrical top-gating of a 2-dimensional electron gas (2DEG) formed at the LaAlO3/SrTiO3 interface, using electron-beam evaporated Au gate electrodes. In these structures, epitaxial LaAlO3 films grown by pulsed laser deposition induce the 2DEGs at the interface to the SrTiO3 substrate and simultaneously act as the gate dielectric. The structured top-gates enable a local tuning and complete on/off switching of the interface (super-)conductivity, while maintaining the usual, intrinsic characteristics for these LaAlO3/SrTiO3 interfaces when no gate voltage is applied.