Similar temperature scale for valence changes in Kondo lattices with different Kondo temperatures.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 29789552.
- Also identified by DOI 10.1038/s41467-018-04438-8 and PMC identifier 5964219.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The Kondo model predicts that both the valence at low temperatures and its temperature dependence scale with the characteristic energy T<sub>K</sub> of the Kondo interaction. Here, we study the evolution of the 4f occupancy with temperature in a series of Yb Kondo lattices using resonant X-ray emission spectroscopy. In agreement with simple theoretical models, we observe a scaling between the valence at low temperature and T<sub>K</sub> obtained from thermodynamic measurements. In contrast, the temperature scale T<sub>v</sub> at which the valence increases with temperature is almost the same in all investigated materials while the Kondo temperatures differ by almost four orders of magnitude. This observation is in remarkable contradiction to both naive expectation and precise theoretical predictions of the Kondo model, asking for further theoretical work in order to explain our findings. Our data exclude the presence of a quantum critical valence transition in YbRh<sub>2</sub>Si<sub>2</sub>.