Intermetallic charge transfer in FeTiO3 probed by resonant inelastic soft x-ray scattering

Resonant inelastic soft x-ray inelastic-scattering (RIXS) spectra of single-crystal iron ilmenite FeTiO3 were measured at the Ti 2p resonance, and additional peaks at -2.5 and -4.5 eV in energy loss were observed. In order to investigate the origin of these peaks, we performed a double-cluster model calculation based on full-multiplet calculation in which, in addition to the interaction with the O 2p ligands of the Ti ion, which is already included in the more conventional single-cluster model, the charge-transfer contribution to Ti 3d from Fe 3d is taken into account. The calculation shows that the peaks may be attributed to the Fe 3d -> Ti 3d intermetallic charge-transfer scheme that previously had not been accounted for in RIXS.