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arXiv · 0902.2251

Direct mapping of the spin-filtered surface bands of a three-dimensional quantum spin Hall insulator

Akinori Nishide·Alexey A. Taskin·Yasuo Takeichi·Taichi Okuda·Akito Kakizaki·Toru Hirahara·Kan Nakatsuji·Fumio Komori·Yoichi Ando·Iwao Matsuda
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Abstract

Spin-polarized band structure of the three-dimensional quantum spin Hall insulator $\rm Bi_{1-x}Sb_{x}$ (x=0.12-0.13) was fully elucidated by spin-polarized angle-resolved photoemission spectroscopy using a high-yield spin polarimeter equipped with a high-resolution electron spectrometer. Between the two time-reversal-invariant points, $\bar{\varGamma}$ and $\bar{M}$, of the (111) surface Brillouin zone, a spin-up band ($Σ_3$ band) was found to cross the Fermi energy only once, providing unambiguous evidence for the strong topological insulator phase. The observed spin-polarized band dispersions determine the "mirror chirality" to be -1, which agrees with the theoretical prediction based on first-principles calculations.

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Akinori Nishide, Alexey A. Taskin, Yasuo Takeichi, Taichi Okuda, Akito Kakizaki, Toru Hirahara, Kan Nakatsuji, Fumio Komori, Yoichi Ando, Iwao Matsuda. 2009-02-13. Direct mapping of the spin-filtered surface bands of a three-dimensional quantum spin Hall insulator. https://doi.org/10.1103/physrevb.81.041309

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