Local Electronic Structure at Oxide-Oxide Interfaces Probed by Atomic Resolution Electron Energy Loss Spectroscopy

We report an atomic resolution study of the electronic structure of 12 x 4 LaMnO$_{3}$-SrMnO$_{3}$ and 2 x 2 LaMnO$_{3}$-SrTiO$_{3}$ superlattices and their interfaces grown on SrTiO$_{3}$ by EELS. We correlated the interfacial electronic structure with the interfacial atomic structure using atomic resolution Z-contrast STEM using an electron probes of $<$0.1 nm. The oxide superlattices were synthesized using molecular beam epitaxy. We measured the site-specific unoccupied states of oxygen atoms and transition metals. In the LMO-SMO system we found extra states (holes) near the Fermi level and their dependence on abruptness of interface. In LMO-STO, we will present evidence of site-dependent electronic structure of oxygen and the Mn valence based on the L-edge ratios.