Metallic interface in non-SrTiO$_3$ based titanate superlattice*

We report on the fabrication of all perovskite Mott insulator/band insulator YTiO$_3$/CaTiO$_3$ superlattices by pulsed laser deposition. The combination of {\it{in-situ}} reflection high energy electron diffraction, X-ray diffraction and X-ray reflectivity confirms the high quality of the films grown in a layer-by-layer mode. Electrical transport measurements reveal that a non-SrTiO$_3$ based two-dimensional electron gas system has formed at the YTiO$_3$/CaTiO$_3$ interface. These studies offer another route in the pursuit of complex oxide two-dimensional electron gas systems which allows to obtain greater insights into the exotic many-body phenomena at such interfaces.