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

doi:10.1021/nl502546c

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)

Nano Lett. 2014 Nov 12;14(11):6226-30. doi: 10.1021/nl502546c. Epub 2014 Oct 31.

Authors

Yuichiro Ando¹, Takahiro Hamasaki, Takayuki Kurokawa, Kouki Ichiba, Fan Yang, Mario Novak, Satoshi Sasaki, Kouji Segawa, Yoichi Ando, Masashi Shiraishi

Affiliation

¹ Department of Electronic Science and Engineering, Kyoto University , Kyoto 615-8531, Japan.

PMID: 25330016
DOI: 10.1021/nl502546c

Abstract

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 Bi1.5Sb0.5Te1.7Se1.3 (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: electrical spin detection; spin current; spin-momentum locking; topological insulator.

Publication types

Research Support, Non-U.S. Gov't