| Autor: |
Kas JJ; Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA., Rehr JJ; Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA.; Department of Photon Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA., Devereaux TP; Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.; Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA. |
| Abstrakt: |
The treatment of electronic correlations in open-shell systems is among the most challenging problems of condensed matter theory. Current approximations are only partly successful. Ligand-field multiplet theory has been widely successful in describing intra-atomic correlation effects in x-ray spectra, but typically ignores itinerant states. The cumulant expansion for the one-electron Green's function has been successful in describing shake-up effects but ignores atomic multiplets. More complete methods, such as dynamic mean-field theory can be computationally demanding. Here, we show that separating the dynamic Coulomb interactions into local and longer-range parts with ab initio parameters yields a combined multiplet-plus-cumulant approach that accounts for both local atomic multiplets and satellite excitations. The approach is illustrated in transition metal oxides and explains the multiplet peaks, charge-transfer satellites, and distributed background features observed in XPS experiment. |
