Electrically controlled spin polarization and selection in a topological insulator sandwiched between ferromagnetic electrodes

Journal Article · Tue Jan 14 00:00:00 EST 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4861743· OSTI ID:22271243

Guo, Junji; Liao, Wenhu; Zhao, Heping ^[1]; Zhou, Guanghui ^[2]

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1. College of Physics, Mechanical and Electrical Engineering, Jishou University, Jishou 416000 (China)
2. Department of Physics and Key Laboratory for Low-Dimensional Quantum Structures and Manipulation (Ministry of Education), Hunan Normal University, Changsha 410081 (China)

We theoretically investigate the electrically controllable spin polarization and selective efficiency of the edge state Dirac electron in a two-dimensional topological insulator (TI) sandwiched between ferromagnetic (FM) electrodes by using the method of Keldysh nonequilibrium Green's function. A nearly full spin polarization of the topological edge state with giant inversion of ∼80% is observed, which is much higher than the value previously reported. Moreover, the selective efficiency for spin-up electrons under the modulation of the parallel configuration of FM electrodes has been demonstrated to be larger than 95% for the first time, while that for spin-down electrons in the antiparallel case is higher than 90% in a wide energy range, owing to the inter-edge spin tunneling induced backscattering and spin dephasing effect. The obtained results may provide a deeper understanding of the TI edge states and a valuable guidance to design spin switch and filter with high on-off speed and selective efficiency based on TIs.

• OSTI ID: 22271243
• Journal Information: Journal of Applied Physics, Vol. 115, Issue 2; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
36 MATERIALS SCIENCE
BACKSCATTERING
DIELECTRIC MATERIALS
DIRAC EQUATION
EFFICIENCY
ELECTRODES
ELECTRONIC STRUCTURE
ELECTRONS
ENERGY LEVELS
FERROMAGNETIC MATERIALS
GREEN FUNCTION
MATHEMATICAL SOLUTIONS
MODULATION
SPIN ORIENTATION
TUNNEL EFFECT