title: Resonant inelastic x-ray scattering at the oxygen K resonance of NiO: nonlocal charge transfer and double-singlet excitations.
abstract: We report high-resolution polarization-dependent resonant inelastic x-ray scattering (RIXS) at the O K resonance of NiO showing a rich excitation spectrum. We perform multisite Ni6O19 cluster model calculations, revealing that solid state effects are substantial. We identify a nonlocal charge transfer excitation at 4-5 eV and double-singlet creation at 1.75 eV, both exhibiting significant scattering geometry dependence. Apart from an intense band of local charge transfer excitations (above 5 eV) also dd excitations at 1 eV are observed. Finally, we point out that O K RIXS of correlated metal oxides allows a quantitative and consistent determination of the charge transfer energy delta and the Hund coupling energy J(H).
authors.affiliation: Department of Physics, Uppsala University, P.O. Box 530, S-751 21 Uppsala, Sweden.
authors.forename: L-C
authors.initials: LC
authors.lastname: Duda
authors.forename: T
authors.initials: T
authors.lastname: Schmitt
authors.forename: M
authors.initials: M
authors.lastname: Magnuson
authors.forename: J
authors.initials: J
authors.lastname: Forsberg
authors.forename: A
authors.initials: A
authors.lastname: Olsson
authors.forename: J
authors.initials: J
authors.lastname: Nordgren
authors.forename: K
authors.initials: K
authors.lastname: Okada
authors.forename: A
authors.initials: A
authors.lastname: Kotani