Electronic structure of the SrTiO3/LaAlO3 interface revealed by resonant soft x-ray scattering

Abstract

Interfaces in heterostructures composed of two different transition-metal oxides are now a strongly growing research topic in condensed-matter physics due to the anomalous electronic properties very different from those of the component materials. Here we present resonant soft x-ray scattering studies of SrTiO3/LaAlO3 superlattices. From the existence of the forbidden Bragg peak (003), we found evidence for differences between the bulk and the interface electronic structures. The photon-energy dependence near the O 1s edge and polarization dependence showed that there are two structures split by ∼ 1 eV, which were not observed in the O 1s x-ray absorption spectrum. The origin of this splitting is still unclear, but we consider that this is not only due to the splitting of t2g states at the interface but also due to the difference between the O 1s binding energies for bulk and interface oxygen. © Published under licence by IOP Publishing Ltd.