Surface Kondo effect and non-trivial metallic state of the Kondo insulator YbB12

Kenta Hagiwara, Yoshiyuki Ohtsubo, Masaharu Matsunami, Shin Ichiro Ideta, Kiyohisa Tanaka, Hidetoshi Miyazaki, Julien E. Rault, Patrick Le Fèvre, François Bertran, Amina Taleb-Ibrahimi, Ryu Yukawa, Masaki Kobayashi, Koji Horiba, Hiroshi Kumigashira, Kazuki Sumida, Taichi Okuda, Fumitoshi Iga, Shin Ichi Kimura

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36 Citations (Scopus)


A synergistic effect between strong electron correlation and spin-orbit interaction has been theoretically predicted to realize new topological states of quantum matter on Kondo insulators (KIs), so-called topological Kondo insulators (TKIs). One TKI candidate has been experimentally observed on the KI SmB6 (001), and the origin of the surface states (SS) and the topological order of SmB6 has been actively discussed. Here, we show a metallic SS on the clean surface of another TKI candidate YbB12 (001) using angle-resolved photoelectron spectroscopy. The SS shows temperature-dependent reconstruction corresponding to the Kondo effect observed for bulk states. Despite the low-temperature insulating bulk, the reconstructed SS with c-f hybridization is metallic, forming a closed Fermi contour surrounding Γ on the surface Brillouin zone and agreeing with the theoretically expected behaviour for SS on TKIs. These results demonstrate the temperature-dependent holistic reconstruction of two-dimensional states localized on KIs surface driven by the Kondo effect.

Original languageEnglish
Article number12690
JournalNature communications
Publication statusPublished - 2016 Aug 31
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)


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