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arXiv · 2303.17816

Spin-polarized saddle points in the topological surface states of the elemental Bismuth revealed by a pump-probe spin-resolved ARPES

Yuto Fukushima·Kaishu Kawaguchi·Kenta Kuroda·Masayuki Ochi·Hiroaki Tanaka·Ayumi Harasawa·Takushi Iimori·Zhigang Zhao·Shuntaro Tani·Koichiro Yaji·Shik Shin·Fumio Komori·Yohei Kobayashi·Takeshi Kondo
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Abstract

We use a pump-probe, spin-, and angle-resolved photoemission spectroscopy (ARPES) with a 10.7 eV laser accessible up to the Brillouin zone edge, and reveal for the first time the entire band structure, including the unoccupied side, for the elemental bismuth (Bi) with the spin-polarized surface states. Our data identify Bi as in a strong topological insulator phase ($Z_2$=1) against the prediction of most band calculations. We unveil that the unoccupied topological surface states possess spin-polarized saddle points yielding the van Hove singularity, providing an excellent platform for the future development of opto-spintronics.

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Yuto Fukushima, Kaishu Kawaguchi, Kenta Kuroda, Masayuki Ochi, Hiroaki Tanaka, Ayumi Harasawa, Takushi Iimori, Zhigang Zhao, Shuntaro Tani, Koichiro Yaji, Shik Shin, Fumio Komori, Yohei Kobayashi, Takeshi Kondo. 2023-03-31. Spin-polarized saddle points in the topological surface states of the elemental Bismuth revealed by a pump-probe spin-resolved ARPES. https://arxiv.org/abs/2303.17816

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