Tuning electronic reconstructions at the cuprate-manganite interface

The electronic properties of CaCuO2/La0.7Sr0.3MnO3 (LSMO) superlattices are determined by the electronic structure of the structural units and in particular their interfaces. The electronic structure of LSMO is governed by a metal-insulator transition, which is controlled by the thickness of the units and the sample temperature, resulting in a systematic downward band shift for metallic samples (i.e., thick LSMO units, low temperature). We present a systematic study of the changes in the valence-band structure and screening features in Mn 2p and Cu 2p core-level spectra. The results show that hybridization of Cu 3d orbitals with out-of-plane O 2p orbitals can be systematically tuned by controlling the band alignment at the interface via the metal-to-insulator transition of the LSMO units. This opens a new route to rational design of functional interfaces and control of orbital reconstructions.