Non-trivial surface states of samarium hexaboride at the (111) surface

Yoshiyuki Ohtsubo; Yuki Yamashita; Kenta Hagiwara; Shin ichiro Ideta; Kiyohisa Tanaka; Ryu Yukawa; Koji Horiba; Hiroshi Kumigashira; Koji Miyamoto; Taichi Okuda; Wataru Hirano; Fumitoshi Iga; Shin ichi Kimura

doi:10.1038/s41467-019-10353-3

Non-trivial surface states of samarium hexaboride at the (111) surface

Yoshiyuki Ohtsubo, Yuki Yamashita, Kenta Hagiwara, Shin ichiro Ideta, Kiyohisa Tanaka, Ryu Yukawa, Koji Horiba, Hiroshi Kumigashira, Koji Miyamoto, Taichi Okuda, Wataru Hirano, Fumitoshi Iga, Shin ichi Kimura

Division of Organic- and Biomaterials Research

Research output: Contribution to journal › Article › peer-review

6 Citations (Scopus)

Abstract

The peculiar metallic electronic states observed in the Kondo insulator, samarium hexaboride (SmB₆), has stimulated considerable attention among those studying non-trivial electronic phenomena. However, experimental studies of these states have led to controversial conclusions mainly due to the difficulty and inhomogeneity of the SmB₆ crystal surface. Here, we show the detailed electronic structure of SmB₆ with angle-resolved photoelectron spectroscopy measurements of the three-fold (111) surface where only two inequivalent time-reversal-invariant momenta (TRIM) exist. We observe the metallic two-dimensional state was dispersed across the bulk Kondo gap. Its helical in-plane spin polarisation around the surface TRIM indicates that SmB₆ is topologically non-trivial, according to the topological classification theory for weakly correlated systems. Based on these results, we propose a simple picture of the controversial topological classification of SmB₆.

Original language	English
Article number	2298
Journal	Nature communications
Volume	10
Issue number	1
DOIs	https://doi.org/10.1038/s41467-019-10353-3
Publication status	Published - 2019 Dec 1

ASJC Scopus subject areas

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

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Non-trivial surface states of samarium hexaboride at the (111) surface. / Ohtsubo, Yoshiyuki; Yamashita, Yuki; Hagiwara, Kenta; Ideta, Shin ichiro; Tanaka, Kiyohisa; Yukawa, Ryu; Horiba, Koji; Kumigashira, Hiroshi; Miyamoto, Koji; Okuda, Taichi; Hirano, Wataru; Iga, Fumitoshi; Kimura, Shin ichi.

In: Nature communications, Vol. 10, No. 1, 2298, 01.12.2019.

Research output: Contribution to journal › Article › peer-review

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title = "Non-trivial surface states of samarium hexaboride at the (111) surface",

abstract = "The peculiar metallic electronic states observed in the Kondo insulator, samarium hexaboride (SmB6), has stimulated considerable attention among those studying non-trivial electronic phenomena. However, experimental studies of these states have led to controversial conclusions mainly due to the difficulty and inhomogeneity of the SmB6 crystal surface. Here, we show the detailed electronic structure of SmB6 with angle-resolved photoelectron spectroscopy measurements of the three-fold (111) surface where only two inequivalent time-reversal-invariant momenta (TRIM) exist. We observe the metallic two-dimensional state was dispersed across the bulk Kondo gap. Its helical in-plane spin polarisation around the surface TRIM indicates that SmB6 is topologically non-trivial, according to the topological classification theory for weakly correlated systems. Based on these results, we propose a simple picture of the controversial topological classification of SmB6.",

author = "Yoshiyuki Ohtsubo and Yuki Yamashita and Kenta Hagiwara and Ideta, {Shin ichiro} and Kiyohisa Tanaka and Ryu Yukawa and Koji Horiba and Hiroshi Kumigashira and Koji Miyamoto and Taichi Okuda and Wataru Hirano and Fumitoshi Iga and Kimura, {Shin ichi}",

note = "Funding Information: The authors thank T. Nakamura, Y. Takeno and C. Wang for their support during general experiments. The authors acknowledge S. Wu for his support during the experiments on BL9B at HiSOR. Part of the ARPES measurements were performed under UVSOR Proposals 29-553 and 30-577, Photon Factory Proposals Nos. 2015G540 and 2017G537, and HiSOR Proposal No. 17AG017. This work was also supported by the JSPS KAKENHI (Grant Nos. JP15H03676, JP17K18757 and JP23244066).",

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AU - Ohtsubo, Yoshiyuki

AU - Yamashita, Yuki

AU - Hagiwara, Kenta

AU - Ideta, Shin ichiro

AU - Tanaka, Kiyohisa

AU - Yukawa, Ryu

AU - Horiba, Koji

AU - Kumigashira, Hiroshi

AU - Miyamoto, Koji

AU - Okuda, Taichi

AU - Hirano, Wataru

AU - Iga, Fumitoshi

AU - Kimura, Shin ichi

N1 - Funding Information: The authors thank T. Nakamura, Y. Takeno and C. Wang for their support during general experiments. The authors acknowledge S. Wu for his support during the experiments on BL9B at HiSOR. Part of the ARPES measurements were performed under UVSOR Proposals 29-553 and 30-577, Photon Factory Proposals Nos. 2015G540 and 2017G537, and HiSOR Proposal No. 17AG017. This work was also supported by the JSPS KAKENHI (Grant Nos. JP15H03676, JP17K18757 and JP23244066).

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