title: Electronic structure of phospho-olivines Li(x)FePO4 (x = 0, 1) from soft-x-ray-absorption and -emission spectroscopies.
abstract: The electronic structure of the phospho-olivine Li(x)FePO4 was studied using soft-x-ray-absorption (XAS) and emission spectroscopies. Characteristic changes in the valence and conduction bands are observed upon delithation of LiFePO4 into FePO4. In LiFePO4, the Fe-3d states are localized with little overlap with the O-2p states. Delithiation of LiFePO4 gives stronger hybridization between Fe-3d states and O-2p states leading to delocalization of the O-2p states. The Fe L-edge absorption spectra yield "fingerprints" of the different valence states of Fe in LiFePO4 and FePO4. Resonant soft-x-ray-emission spectroscopy at the Fe L edge shows strong contributions from resonant inelastic soft x-ray scattering (RIXS), which is described using an ionic picture of the Fe-3d states. Together the Fe L-edge XAS and RIXS study reveals a bonding character of the Fe 3d-O2p orbitals in FePO4 in contrast to a nonbonding character in LiFePO4.
authors.affiliation: Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: A
authors.initials: A
authors.lastname: Augustsson
authors.forename: G V
authors.initials: GV
authors.lastname: Zhuang
authors.forename: S M
authors.initials: SM
authors.lastname: Butorin
authors.forename: J M
authors.initials: JM
authors.lastname: Osorio-Guillén
authors.forename: C L
authors.initials: CL
authors.lastname: Dong
authors.forename: R
authors.initials: R
authors.lastname: Ahuja
authors.forename: C L
authors.initials: CL
authors.lastname: Chang
authors.forename: P N
authors.initials: PN
authors.lastname: Ross
authors.forename: J
authors.initials: J
authors.lastname: Nordgren
authors.forename: J-H
authors.initials: JH
authors.lastname: Guo