Electronic Structure of Protonic Conductor BaCe_0.90Y_0.10O_3-δ Probed by Soft-X-Ray Spectroscopy

Abstract

The electronic structure of the protonic conductor Y-doped BaCeO 3 (BaCe 0.90 Y 0.10 O 3-δ ) has been studied by photoemission spectroscopy and X-ray absorption spectroscopy. The Fermi level ( E F ) of H 2 -annealed BaCe 0.90 Y 0.10 O 3-δ shifts to the conduction band side by approximately 0.4 eV. The holes and acceptor level are observed at the top of the valence band and just above E F , respectively. Their intensities are lower in the H 2 -annealed BaCe 0.90 Y 0.10 O 3-δ , indicating that doped hydrogen enters hole and acceptor states. These findings indicate that the electronic structure of the protonic conductor BaCe 0.90 Y 0.10 O 3-δ obeys the rigid-band model.