Kondo scale and coupled fluorescence across the γ-α transition in Ce 0.93 Sc 0.07
Résumé
We present a resonant inelastic x-ray scattering (RIXS) study across the temperature (T) driven γ-α transition in Ce 0.93 Sc 0.07. RIXS measurements across the Ce M 5 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, U f 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.
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