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TT: Fachverband Tiefe Temperaturen
TT 9: f-Electron Systems and Heavy Fermions II
TT 9.4: Talk
Monday, March 27, 2023, 15:45–16:00, HSZ 201
High-resolution tender x-ray RIXS at the example of UGa2 — •Martin Sundermann1,2, Andrea Marino1, Denise Christovam1, Andrea Amorese1,3, Ladislav Havela4, Bernhard Keimer5, Hlynur Gretarsson1,2,5, Peter Thalmeier1, Liu Hao Tjeng1, and Andrea Severing1,3 — 1MPI-CPfS, Dresden, Germany — 2DESY/PETRA-III, Hamburg, Germany — 3Institute of Physics II, University of Cologne, Germany — 4Condensed Matter Physics, Karls-Universität, Prag, Czech — 5MPI-FKF, Stuttgart, Germany
The nature of the 5f electrons in U intermetallic compounds, usually thought to be on the verge between localization and itinerant states, still challenges the reach of well-established condensed matter physics’ techniques. Yet, it is not uncommon that U-based compounds show no inelastic neutron scattering excitations, and the question remains, if these compounds are fully delocalized or if multiplet states are present but not observable. Cutting-edge instrumental developments enables us to perform tender x-ray high-resolution (150 meV) resonant inelastic X-ray scattering (RIXS) experiments at the strong U M4,5 absorption edges. We demonstrate the potential of this technique at the example of the intermetallic high TC ferromagnet UGa2. We observe mutliplet excitations that are well reproduced with a full multiplet calculation that includes the crystal-electron field splitting and is based on an U 5f2 configuration. Further we show that, although crystal-field splittings are too small to be resolved, the directional dependence of the scattering cross-section gives access to the ground-state symmetry.