Interfacial Electronic Properties of LaAlO$_{3}$/SrTiO$_{3}$ superlattice Probed with Hard X-ray Photoemission

Unexpected electronic and magnetic properties at interfaces between distinct transition-metal oxides have received much attention recently. The electronic phase at the interface of a heterostructure often differs from those of the sandwiching bulks. For instance, the interface between two band insulators LaAlO$_{3}$ and SrTiO$_{3}$ exhibits rich interfacial phases, drastically different from their original bulks. Here we will present measurements of hard X-ray photoemission and x-ray absorption on a LaAlO$_{3}$/SrTiO$_{3}$ superlattice to address the issue of interfacial electron at interfaces.