Intermetallic charge transfer and band gap of MTiO3 (M=Mn, Fe, Co, and Ni) studied by O 1s-edge X-ray emission spectroscopy

Charge transfer is a key concept in understanding X-ray spectra of transition metal oxides. In this study, X-ray absorption spectra (XAS) and X-ray emission spectra (XES) at the O 1 s -edge of MTiO 3 (ilmenite: M = Mn, Fe, Co, and Ni) have been measured. It was found that the O 1 s -edge XES show the existence of not only oxygen–metal charge transfer but also intermetallic charger transfer. Moreover, the band gap of each ilmenite was evaluated to be 2.4–2.8 eV by measuring the distance between the spectra edges of XAS and XES.