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arXiv · 1412.3162

Electrical detection of the spin polarization due to charge flow in the surface state of the topological insulator Bi_1.5 Sb_0.5 Te_1.7 Se_1.3

Yuichiro Ando·Takahiro Hamasaki·Takayuki Kurokawa·Kouki Ichiba·Fan Yang·Mario Novak·Satoshi Sasaki·Kouji Segawa·Yoichi Ando·Masashi Shiraishi
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Abstract

We detected the spin polarization due to charge flow in the spin non-degenerate surface state of a three dimensional topological insulator by means of an all-electrical method. The charge current in the bulk-insulating topological insulator Bi1.5Sb0.5Te1.7Se1.3 (BSTS) was injected/extracted through a ferromagnetic electrode made of Ni80Fe20, and an unusual current-direction-dependent magnetoresistance gives evidence for the appearance of spin polarization which leads to a spin-dependent resistance at the BSTS/Ni80Fe20 interface. In contrast, our control experiment on Bi2Se3 gave null result. These observations demonstrate the importance of the Fermi-level control for the electrical detection of the spin polarization in topological insulators.

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Yuichiro Ando, Takahiro Hamasaki, Takayuki Kurokawa, Kouki Ichiba, Fan Yang, Mario Novak, Satoshi Sasaki, Kouji Segawa, Yoichi Ando, Masashi Shiraishi. 2014-12-10. Electrical detection of the spin polarization due to charge flow in the surface state of the topological insulator Bi_1.5 Sb_0.5 Te_1.7 Se_1.3. https://doi.org/10.1021/nl502546c

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