Electrical Detection of the Spin Polarization Due to Charge Flow in the Surface State of the Topological Insulator Bi sub(1.5)Sb sub(0.5)Te sub(1.7)Se sub(1.3)

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 sub(1.5)Sb sub(0.5)Te sub(1.7)Se sub(1.3) (BSTS) was inje...

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Bibliographic Details
Published in:Nano letters 2014-11, Vol.14 (11), p.6226-6230
Main Authors: Ando, Yuichiro, Hamasaki, Takahiro, Kurokawa, Takayuki, Ichiba, Kouki, Yang, Fan, Novak, Mario, Sasaki, Satoshi, Segawa, Kouji, Ando, Yoichi, Shiraishi, Masashi
Format: Article
Language:English
Subjects:
Charge
Electric charge
Electrodes
Insulators
Magnetoresistivity
Polarization
Three dimensional
Topology
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Summary: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 sub(1.5)Sb sub(0.5)Te sub(1.7)Se sub(1.3) (BSTS) was injected/extracted through a ferromagnetic electrode made of Ni sub(80)Fe sub(20), 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/Ni sub(80)Fe sub(20) interface. In contrast, our control experiment on Bi sub(2)Se sub(3) 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
ISSN:1530-6984
1530-6992
DOI:10.1021/nl502546c