The electronic structure of Ba1−xCaxTiO3 probed by X-ray absorption spectroscopy

We report O K-, Ca K- and L3,2-, and Ti L3,2-edge X-ray absorption near edge structure (XANES) spectra of Ba1−xCaxTiO3 (x=0, 0.01, 0.08, and 1) and the electronic properties inferred from these XANES spectra. The spectra of O K-, Ca L3,2- and Ti L3,2-edges show characteristic spectral features attributable to the t2g and eg bands. The Ti and Ca L3,2-edge spectra contain two sets of L3 and L2 features with a L3–L2 separation of about 5.5 and 3.4eV, respectively. We also observe a pre-edge feature in the Ca K-edge spectra and drastically reduced t2g features in the Ca L3,2-edge spectra. Our XANES spectra reveal that the Ca 3d bands are low-lying and the Ca 3d t2g bands are partially occupied.