Electronic Reconstruction at SrMnO₃-LaMnO₃ Superlattice Interfaces

We use resonant soft–x-ray scattering (RSXS) to study the electronic reconstruction at the interface between the Mott insulator LaMnO₃ and the band insulator SrMnO₃. Superlattices of these two insulators were shown previously to have both ferromagnetism and metallic tendencies [ Koida et al. Phys. Rev. B 66 144418 (2002)]. By studying a judiciously chosen superlattice reflection, we show that the interface density of states exhibits a pronounced peak at the Fermi level, similar to that predicted in related titanate superlattices by Okamoto et al. [ Phys. Rev. B 70 241104(R) (2004)]. The intensity of this peak correlates with the conductivity and magnetization, suggesting it is the driver of metallic behavior. Our study demonstrates a general strategy for using RSXS to probe the electronic properties of heterostructure interfaces.