Open AccessTruly bulk‐sensitive spectroscopic measurements of valence in heavy fermion materials
Author(s) -
Dallera Claudia,
Grioni Marco,
Shukla Abhay,
Vankò Gyorgy,
Sarrao John L.
Publication year - 2002
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s0909049502004879
Subject(s) - heavy fermion , valence (chemistry) , fermion , physics , materials science , condensed matter physics , chemical physics , quantum mechanics , superconductivity
Intermediate valence is one of the typical phenomena of systems with strong electronic correlation. The Anderson impurity model predicts a scaling of the valence with the reduced temperature T / T K , which is difficult to observe by traditional surface‐sensitive electronic spectroscopies. This paper presents results obtained by resonant inelastic X‐ray scattering (RIXS), a bulk‐sensitive configuration‐ and chemical‐specific technique. The temperature dependence of the valence of YbInCu 4 and YbAgCu 4 was measured by tuning the incident energy to the resonance of the Yb 2+ spectral component. In the case of YbInCu 4 a sharp valence transition, as known from thermodynamical measurements, has been found. The valence of YbAgCu 4 reveals a smooth dependence consistent with a Kondo temperature T K = 70 K. These findings establish RIXS as a powerful tool for measuring bulk electronic properties of solids.