title: New spectroscopy solves an old puzzle: the Kondo scale in heavy fermions.
abstract: Resonant inelastic x-ray scattering (RIXS) yields clear evidence of spectroscopic Kondo scales in heavy fermions. In YbInCu4 and YbAgCu4 RIXS probes the Yb2+ component of the hybrid ground state and the temperature dependence of the Yb 4f occupation. We report a sudden valence change at a phase transition in YbInCu4, but a continuous temperature dependence in YbAgCu4, consistent with the predictions of the Anderson impurity model, for a Kondo temperature T(K) = 70 K. These results solve a long-standing controversy and establish RIXS as a quantitative probe of the electronic structure of strongly correlated electron systems.
authors: INFM-Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy.
authors: C
authors: C
authors: Dallera
authors: M
authors: M
authors: Grioni
authors: A
authors: A
authors: Shukla
authors: G
authors: G
authors: Vankó
authors: J L
authors: JL
authors: Sarrao
authors: J P
authors: JP
authors: Rueff
authors: D L
authors: DL
authors: Cox