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  Tegomo Chiogo, B.; Nicolaou, A.; Schweitzer, T.; Mazet, T.; Chainani, A.; Malterre, D.: Kondo scale and coupled fluorescence across the γ-α transition in Ce_0.93Sc_0.07. Physical Review B 108 (2023), p. 195110/1-8

10.1103/PhysRevB.108.195110
Open Access Version (available 01.12.2024)

Abstract:
We present a resonant inelastic x-ray scattering (RIXS) study across the temperature (T) driven γ -α transition in Ce0.93Sc0.07. RIXS measurements across the CeM5 edge unambiguously identify the f 1 → f 0 and f 1 → f 2 charge excitations, which provide a quantification of the Ce on-site Coulomb repulsion energy, Uf f . Calculation with a simplified single-impurity Anderson model combined with full multiplet theory reproduces the charge excitations and establishes that the very different Kondo temperatures of the γ to α phase are reflected in RIXS spectra. A systematic T -dependent hysteresis is observed for the f 0 final state spectral intensity upon cycling across the γ -α transition. In addition, a fluorescencelike structure also follows the same hysteretic behavior and shows it is directly connected to the weight of the f 0 configuration in the ground state. The results indicate that the Ce M-edge RIXS is a reliable quantitative probe of the electronic structure of strongly correlated Ce-based Kondo systems and is sensitive to the emergent Kondo energy scale.