Electronic structure and evolution of the orbital state in metallic Ca2-xSrxRuO4 -: art. no. 052411

We investigated the electronic structure of a layered Ca2-xSrxRuO4 in a metallic regime (0.15 <= x <= 2.0) using a polarization dependent O 1s x-ray absorption spectroscopy. The spectrum shows strong variations with the polarization especially in Ru 4d region, which enables us to identify the electronic states. The spectral line shape gradually changes with increase of Sr concentration, and agrees well with an unrestricted Hartree-Fock analysis, which suggests evolution of the orbital states and provides clues for how the lattice distortion affects the orbital occupations.