Electrical Detection of the Spin Polarization Due to Charge Flow in the Surface State of the Topological Insulator Bi1.5Sb0.5Te1.7Se1.3

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• 作者：Yuichiro Ando ; Takahiro Hamasaki ; Takayuki Kurokawa ; Kouki Ichiba ; Fan Yang ; Mario Novak ; Satoshi Sasaki ; Kouji Segawa ; Yoichi Ando ; Masashi Shiraishi
• 刊名：Nano Letters
• 出版年：2014
• 出版时间：November 12, 2014
• 年：2014
• 卷：14
• 期：11
• 页码：6226-6230
• 全文大小：368K
• ISSN：1530-6992

文摘

We detected the spin polarization due to charge flow in the spin nondegenerate surface state of a three-dimensional topological insulator by means of an all-electrical method. The charge current in the bulk-insulating topological insulator Bi_1.5Sb_0.5Te_1.7Se_1.3 (BSTS) was injected/extracted through a ferromagnetic electrode made of Ni₈₀Fe₂₀, and an unusual current-direction-dependent magnetoresistance gave 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.

Keywords:

topological insulator; spin-momentum locking; spin current; electrical spin detection