TY - JOUR

T1 - Similar temperature scale for valence changes in Kondo lattices with different Kondo temperatures

AU - Kummer, K.

AU - Geibel, C.

AU - Krellner, C.

AU - Zwicknagl, G.

AU - Laubschat, C.

AU - Brookes, N. B.

AU - Vyalikh, D. V.

PY - 2018/5/22

Y1 - 2018/5/22

N2 - The Kondo model predicts that both the valence at low temperatures and its temperature dependence scale with the characteristic energy T K 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 K obtained from thermodynamic measurements. In contrast, the temperature scale T v 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 YbRh2Si2.

AB - The Kondo model predicts that both the valence at low temperatures and its temperature dependence scale with the characteristic energy T K 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 K obtained from thermodynamic measurements. In contrast, the temperature scale T v 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 YbRh2Si2.

KW - QUANTUM CRITICAL-POINT

KW - 4F QUADRUPOLE-MOMENT

KW - CRYSTAL-GROWTH

KW - METAL YBRH2SI2

KW - HEAVY

KW - SUPERCONDUCTIVITY

KW - DEPENDENCE

KW - TRANSITION

KW - YBIR2SI2

KW - STATE

UR - http://www.scopus.com/inward/record.url?scp=85047725141&partnerID=8YFLogxK

U2 - 10.1038/s41467-018-04438-8

DO - 10.1038/s41467-018-04438-8

M3 - Article

C2 - 29789552

AN - SCOPUS:85047725141

VL - 9

JO - Nature Communications

JF - Nature Communications

SN - 2041-1723

IS - 1

M1 - 2011

ER -