The electronic structures of BiFeO3 (BF) and Mn-doped BiFeO3 [BF(Mn)] have been studied by X-ray absorption spectroscopy (XAS) and soft-X-ray emission spectroscopy (SXES). BF and BF(Mn) have a mixed valence state of Fe2+ and Fe3+. Their valence band is mainly composed of the O 2p state hybridized with the majority-spin t2g and eg orbitals of Fe 3d state. The conduction band is composed of the minority-spin t2g and eg orbitals of Fe 3d. The band gaps of BF and BF(Mn) are estimated to be 1.3 eV and 2.7 eV, respectively. The increase in band gap with Mn substitution contributes to a change in the bandwidth of the valence band.
Japanese Journal of Applied Physics 47(9), pp.7570-7573