Electronic structure and magnetic states in ${\mathrm{La}}_{1-x}$${\mathrm{Sr}}_x{\mathrm{CoO}}_3$ studied by photoemission and x-ray-absorption spectroscopy

We have studied the effects of hole doping on the electronic structure of La${}_{1-x}$Sr${}_x$CoO${}_3$ by photoemission and x-ray-absorption spectroscopy. The Co 2$p$ core-level and the valence-band spectra show charge-transfer satellites, which have been more obviously observed in 3$p$-3$d$ resonant-photoemission spectra. By Sr substitution for La in LaCoO${}_3$, the valence-band spectra do not show rigid-band behavior but change systematically and reflect the semiconductor-to-metal transition which occurs with hole doping. Only small changes with $x$ have been observed in the resonant-photoemission spectra. Combined with configuration-interaction cluster-model calculations, this observation suggests that the intermediate-spin state is realized in the ferromagnetic phase.