X-ray photoemission measurements of La1-xCaxCoO3 (x=0, 0.5)

X-ray photoemission measurements of the core levels and valence electronic structure of LaCoO3 and La0.5Ca0.5CoO3 high quality epitaxial films are presented. Shifts of the core levels and main valence band features are consistent with a doping-induced change in the chemical potential. Oxygen states are found ro significantly contribute to a peak in the valence band at I eV binding energy, verifying earlier results of cluster calculations. A Fermi level crossing of this same band upon doping is observed, yielding a high Fermi-level density of states.