Transport properties of ultrathin oxide films and nanostructures

We have studied the transport properties of thin LaTiO3 films, grown on NdGaO3 and SrTiO3 substrates. In case of films grown on NdGaO3 we see a sharp increase of film resistivity when the film thickness drops below 18 nm. This appears to correspond to a surface depletion layer in the films. We could avoid the detrimental effects of surface states by growing LaTiO3 films on SrTiO3 substrates and covering the LaTiO3 layers with a SrTiO3 cap layer. In this case we succeeded in fabricating isolated LaTiO3 layers, sandwiched between SrTiO3, that remained metallic down to 4 K. This work shows that it is feasible to use the LaTiO3/SrTiO3 system for growing metallic nanostructure arrays.