Electronic structure of protonic conductor SrCeO3 by soft-X-ray spectroscopy

The electronic structure of protonic conductor SrCe1-xYxO3-delta (x=0, 0.05) has been studied by resonant-photoemission spectroscopy (RPES) and X-ray absorption spectroscopy (XAS) in the soft-X-ray region. The RPES spectra exhibit that the O 2p state strongly hybridizes with Ce 4f state in the valence band. The valence band consists of the mixed-valent states of the 4f(0) (Ce4+) and 4f(1)(L) under bar (Ce3+) Configurations. The XAS spectra in the band gap energy region show a hole state at the top of the valence band and an acceptor-induced level just above the Fermi level (E-F). The energy position of the hole state accords with that of the Cc 31 state. The energy separation between the hole state and EF is ill good agreement with the activation energy. (C) 2004 Elsevier B.V. All rights reserved.