Electronic Structure of Ilmenite and Ilmenite-Hematite Solid Solution Using Hard X-Ray Photoemission Spectroscopy

抄録

We have conducted hard X-ray photoemission spectroscopy on FeTiO₃ and FeTiO₃–Fe₂O₃ solid solution in order to examine the electronic structure and electrical conduction mechanism of the compounds. The valence band spectrum of FeTiO₃–Fe₂O₃ solid solution manifests a clear peak shift compared to FeTiO₃, indicating that the electronic structure of FeTiO₃–Fe₂O₃ solid solution consists of strongly mixed Fe 3d and O 2p components and that the electron correlation of the Fe 3d components is varied by the formation of solid solution between FeTiO₃ and α–Fe₂O₃. We propose that insulating FeTiO₃ is converted into semiconductor via this mechanism by the formation of FeTiO₃–Fe₂O₃ solid solution, and the electron transfer between Fe²⁺ and Fe³⁺ in C-plane dominantly contributes to the electrical conduction in FeTiO₃–Fe₂O₃ solid solution.