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Unexpected differences between surface and bulk spectroscopic and implied Kondo properties of heavy fermion CeRh2Si2

Poelchen, Georg ; Schulz, Susanne ; Mende, Max ; Güttler, Monika ; Generalov, Alexander LU ; Fedorov, Alexander V. ; Caroca-Canales, Nubia ; Geibel, Christoph ; Kliemt, Kristin and Krellner, Cornelius , et al. (2020) In npj Quantum Materials 5(1).
Abstract

Ultra-violet angle-resolved photoemission spectroscopy (UV-ARPES) was used to explore the temperature dependence of the Ce-4f spectral responses for surface and bulk in the antiferromagnetic Kondo lattice CeRh2Si2. Spectra were taken from Ce- and Si-terminated surfaces in a wide temperature range, and reveal characteristic 4f patterns for weakly (surface) and strongly (bulk) hybridized Ce, respectively. The temperature dependence of the Fermi level peak differs strongly for both cases implying that the effective Kondo temperature at the surface and bulk can be rather distinct. The greatly reduced crystal–electric-field (CEF) splitting at the surface gives reason to believe that the surface may exhibit a larger... (More)

Ultra-violet angle-resolved photoemission spectroscopy (UV-ARPES) was used to explore the temperature dependence of the Ce-4f spectral responses for surface and bulk in the antiferromagnetic Kondo lattice CeRh2Si2. Spectra were taken from Ce- and Si-terminated surfaces in a wide temperature range, and reveal characteristic 4f patterns for weakly (surface) and strongly (bulk) hybridized Ce, respectively. The temperature dependence of the Fermi level peak differs strongly for both cases implying that the effective Kondo temperature at the surface and bulk can be rather distinct. The greatly reduced crystal–electric-field (CEF) splitting at the surface gives reason to believe that the surface may exhibit a larger effective Kondo temperature because of a higher local-moment effective degeneracy. Further, the hybridization processes could strongly affect the 4f peak intensity at the Fermi level. We derived the k-resolved dispersion of the Kondo peak which is also found to be distinct due to different sets of itinerant bands to which the 4f states of surface and bulk Ce are coupled. Overall our study brings into reach the ultimate goal of quantitatively testing many-body theories that link spectroscopy and transport properties, for both the bulk and the surface, separately. It also allows for a direct insight into the broader problem of Kondo lattices with two different local-moment sublattices, providing some understanding of why the cross-talking between the two Kondo effects is weak.

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type
Contribution to journal
publication status
published
subject
in
npj Quantum Materials
volume
5
issue
1
article number
70
publisher
Nature Publishing Group
external identifiers
  • scopus:85092044209
ISSN
2397-4648
DOI
10.1038/s41535-020-00273-7
language
English
LU publication?
yes
id
f07e5c62-e37f-4815-8191-94b2f3980424
date added to LUP
2020-10-28 13:52:26
date last changed
2022-04-19 01:26:49
@article{f07e5c62-e37f-4815-8191-94b2f3980424,
  abstract     = {{<p>Ultra-violet angle-resolved photoemission spectroscopy (UV-ARPES) was used to explore the temperature dependence of the Ce-4f spectral responses for surface and bulk in the antiferromagnetic Kondo lattice CeRh<sub>2</sub>Si<sub>2</sub>. Spectra were taken from Ce- and Si-terminated surfaces in a wide temperature range, and reveal characteristic 4f patterns for weakly (surface) and strongly (bulk) hybridized Ce, respectively. The temperature dependence of the Fermi level peak differs strongly for both cases implying that the effective Kondo temperature at the surface and bulk can be rather distinct. The greatly reduced crystal–electric-field (CEF) splitting at the surface gives reason to believe that the surface may exhibit a larger effective Kondo temperature because of a higher local-moment effective degeneracy. Further, the hybridization processes could strongly affect the 4f peak intensity at the Fermi level. We derived the k-resolved dispersion of the Kondo peak which is also found to be distinct due to different sets of itinerant bands to which the 4f states of surface and bulk Ce are coupled. Overall our study brings into reach the ultimate goal of quantitatively testing many-body theories that link spectroscopy and transport properties, for both the bulk and the surface, separately. It also allows for a direct insight into the broader problem of Kondo lattices with two different local-moment sublattices, providing some understanding of why the cross-talking between the two Kondo effects is weak.</p>}},
  author       = {{Poelchen, Georg and Schulz, Susanne and Mende, Max and Güttler, Monika and Generalov, Alexander and Fedorov, Alexander V. and Caroca-Canales, Nubia and Geibel, Christoph and Kliemt, Kristin and Krellner, Cornelius and Danzenbächer, Steffen and Usachov, Dmitry Yu and Dudin, Pavel and Antonov, Victor N. and Allen, James W. and Laubschat, Clemens and Kummer, Kurt and Kucherenko, Yuri and Vyalikh, Denis V.}},
  issn         = {{2397-4648}},
  language     = {{eng}},
  month        = {{12}},
  number       = {{1}},
  publisher    = {{Nature Publishing Group}},
  series       = {{npj Quantum Materials}},
  title        = {{Unexpected differences between surface and bulk spectroscopic and implied Kondo properties of heavy fermion CeRh<sub>2</sub>Si<sub>2</sub>}},
  url          = {{http://dx.doi.org/10.1038/s41535-020-00273-7}},
  doi          = {{10.1038/s41535-020-00273-7}},
  volume       = {{5}},
  year         = {{2020}},
}