Dehybridization of f and d states in the heavy-fermion system YbRh2Si2

D. Leuenberger, J. A. Sobota, S.-L. Yang, H. Pfau, D.-J. Kim, S.-K. Mo, Z. Fisk, P. S. Kirchmann, and Z.-X. Shen
Phys. Rev. B 97, 165108 – Published 6 April 2018

Abstract

We report an optically induced reduction of the fd hybridization in the prototypical heavy-fermion compound YbRh2Si2. We use femtosecond time- and angle-resolved photoemission spectroscopy to monitor changes of spectral weight and binding energies of the Yb 4f and Rh 4d states before the lattice temperature increases after pumping. Overall, the fd hybridization decreases smoothly with increasing electronic temperature up to 250K but changes slope at 100K. This temperature scale coincides with the onset of coherent Kondo scattering and with thermally populating the first excited crystal electrical field level. Extending previous photoemission studies, we observe a persistent fd hybridization up to at least 250K, which is far larger than the coherence temperature defined by transport but in agreement with the temperature dependence of the noninteger Yb valence. Our data underlines the distinction of probes accessing spin and charge degrees of freedom in strongly correlated systems.

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  • Received 24 February 2018

DOI:https://doi.org/10.1103/PhysRevB.97.165108

©2018 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

D. Leuenberger1,2, J. A. Sobota1,2,3, S.-L. Yang1,2,*, H. Pfau1,4, D.-J. Kim5, S.-K. Mo3, Z. Fisk5, P. S. Kirchmann1,†, and Z.-X. Shen1,2,4,‡

  • 1Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
  • 2Geballe Laboratory for Advanced Materials, Department of Applied Physics, Stanford University, Stanford, California 94305, USA
  • 3Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
  • 4Department of Physics, Stanford University, Stanford, California 94305, USA
  • 5Department of Physics and Astronomy, University of California, Irvine, California 92697, USA

  • *Present address: Kavli Institute at Cornell for Nanoscale Science, Laboratory of Atomic and Solid State Physics, Department of Physics, and Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA.
  • kirchman@stanford.edu
  • zxshen@stanford.edu

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Issue

Vol. 97, Iss. 16 — 15 April 2018

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