Intermetallic charge transfer in FeTiO probed by resonant inelastic soft X-ray scattering

Agui, Akane; Uozumi, Takayuki*; Mizumaki, Masaichiro*; Kmbre, T.*

We studied the electronic structure of FeTiO. The experimental technique used in this study was Ti 2 soft resonant X-ray inelastic scattering spectroscopy (RIXS) and it was carried out at I511-3 at MAX-lab. FeTiO has the ilmenite structure and this is an ordered corundum structure. Ions of Fe and Ti occupy the basal cation planes alternatively in which Fedivalent and Ti is tetravalent. Local symmetry around transition metal ions, both Fe and Ti, are in the distorted Oh symmetry. Butorin et al had reported the RIXS spectra of Ti La,b (Phy. Rev. B55 (1997) 4242) in the 3 compounds and discussed the charge-transfer transitions from Ti 3 - O 2 hybridization. In this study, we measured Ti La,b RIXS of FeTiO in detail and the spectra shows rich resonant feature. When the excitation energy is tuned at the well-defined peak of Ti L3 X-ray absorption spectrum (XAS), a clear small peak appears at 2.5 eV below from the elastic peak. An additional peak comes up at 4.5 eV below the elastic peak when the excitation energy is tuned at the well defined peak of XAS. The spectral features are attributed to eg and state of Ti 3 due to crystal field and charge transfer between Ti 3 and O 2. We are analyzing the RIXS spectra within the cluster model in order to investigate the clear resonant peaks. By demonstrating a double-cluster model calculation taking into account offull-multiplet, we conclude that the origin of features are attributed to Fe 3 Ti 3 charge transfer process with - charge transfer form Fe to Ti, e.g. it is due to inter-metallic charge transfer, which is a new essential elementary optical process in RIXS study.