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

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.
Authors:
; ;  [1] ;  [2]
  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)
Publication Date:
OSTI Identifier:
22271243
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 2; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
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