Temperature-Independent Fermi Surface in the Kondo Lattice YbRh2Si2

K. Kummer (1) , S. Patil (2) , A. Chikina (2) , M. Guettler (2) , M. Hoeppner (3, 2) , A. Generalov (2) , S. Danzenbaecher (2) , S. Seiro (4) , A. Hannaske (4) , C. Krellner (5) , Yu Kucherenko (6, 2) , Minghua Shi (7) , M. Radovic (7) , E. Rienks (8) , G. Zwicknagl (9) , K. Matho (10, 11) , J. W. Allen (12) , C. Laubschat (2) , C. Geibel (4) , D. V. Vyalikh (13, 2)

1 ESRF - European Synchrotron Radiation Facility
2 Tech Univ Dresden, Inst Solid State Phys, D-01062 Dresden, Germany
3 Max Planck Institute for Solid State Research
4 CPfS - Max Planck Institute for Chemical Physics of Solids
5 Goethe-Universität Frankfurt am Main
6 Natl Acad Sci Ukraine, Inst Met Phys, UA-03142 Kiev, Ukraine
7 Paul Scherrer Inst, Swiss Light Source, CH-5232 Villigen, Switzerland
8 BESSY II
9 Tech Univ Carolo Wilhelmina Braunschweig, Inst Math Phys, D-38106 Braunschweig, Germany
10 NEEL - TMC - Théorie de la Matière Condensée
11 UGA [2016-2019] - Université Grenoble Alpes [2016-2019]
12 University of Michigan [Ann Arbor]
13 St Petersburg State Univ, Dept Phys, St Petersburg 198504, Russia

Strongly correlated electron systems are one of the central topics in contemporary solid-state physics. Prominent examples for such systems are Kondo lattices, i.e., intermetallic materials in which below a critical temperature, the Kondo temperature T-K, the magnetic moments become quenched and the effective masses of the conduction electrons approach the mass of a proton. In Ce-and Yb-based systems, this so-called heavy-fermion behavior is caused by interactions between the strongly localized 4f and itinerant electrons. A major and very controversially discussed issue in this context is how the localized electronic degree of freedom gets involved in the Fermi surface (FS) upon increasing the interaction between both kinds of electrons or upon changing the temperature. In this paper, we show that the FS of a prototypic Kondo lattice, YbRh2Si2, does not change its size or shape in a wide temperature range extending from well below to far above the single-ion Kondo temperature T-K similar to 25 K of this system. This experimental observation, obtained by means of angle-resolved photoemission spectroscopy, is in remarkable contrast to the widely believed evolution from a large FS, including the 4f degrees of freedom, to a small FS, without the 4f's, upon increasing temperature. Our results explicitly demonstrate a need to further advance in theoretical approaches based on the periodic Anderson model in order to elucidate the temperature dependence of Fermi surfaces in Kondo lattices

Domaines: Physique [physics]

K. Kummer, S. Patil, A. Chikina, M. Guettler, M. Hoeppner, et al.. Temperature-Independent Fermi Surface in the Kondo Lattice YbRh2Si2. Physical Review X, 2015, 5 (1), pp.011028. ⟨10.1103/PhysRevX.5.011028⟩. ⟨hal-01572722⟩