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TT: Fachverband Tiefe Temperaturen

TT 42: Correlated Electrons: f-Electron Systems and Heavy Fermions 2

TT 42.10: Vortrag

Mittwoch, 18. März 2020, 17:30–17:45, HSZ 204

Resonant X-Ray Emission Spectra: Effects of the Final-State Core Hole — •Jindrich Kolorenc — Institute of Physics, Czech Academy of Sciences, Prague, Czech Republic

The resolution of the x-ray absorption spectroscopy is fundamentally limited by the life-time broadening of the core hole created in the absorption event. When the absorption is detected by monitoring a particular core-to-core emission process of filling the created hole (for instance, the 3d→2p transition in the case of lanthanide L edges), the broadening is reduced and it is determined by a considerably longer life time of the shallower 3d hole remaining in the final state [1]. This is not always the whole story – there can be a sizable exchange interaction between the final-state core hole and some partially filled valence shell (this would be the 4f shell in the lanthanide example). The exchange interaction causes multiplet splitting that reduces the resolution again and potentially even introduces spurious features to the deduced absorption spectra. I will discuss these effects theoretically using the atomic model and the Anderson impurity model. I will show under which simplifying conditions the many-body part of the problem reduces to evaluation of a propagator of the final-state core hole, a quantity that is measured by the x-ray photoemission.

[1] K. Hamalainen, D. P. Siddons, J. B. Hastings, L. E. Berman, Phys. Rev. Lett. 67, 2850 (1991).