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Title: Spin force and the generation of sustained spin current in time-dependent Rashba and Dresselhaus systems

The generation of spin current and spin polarization in a two-dimensional electron gas structure is studied in the presence of Dresselhaus and Rashba spin-orbit couplings (SOC), the strength of the latter being modulated in time by an ac gate voltage. By means of the non-Abelian gauge field approach, we established the relation between the Lorentz spin force and the spin current in the SOC system, and showed that the longitudinal component of the spin force induces a transverse spin current. For a constant (time-invariant) Rashba system, we recover the universal spin Hall conductivity of e/(8π) , derived previously via the Berry phase and semi-classical methods. In the case of a time-dependent SOC system, the spin current is sustained even under strong impurity scattering. We evaluated the ac spin current generated by a time-modulated Rashba SOC in the absence of any dc electric field. The magnitude of the spin current reaches a maximum when the modulation frequency matches the Larmor frequency of the electrons.
Authors:
;  [1] ;  [2] ;  [1]
  1. Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore)
  2. (A-STAR), DSI Building, 5 Engineering Drive 1, Singapore 117608 (Singapore)
Publication Date:
OSTI Identifier:
22275565
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 18; 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; ELECTRIC CONDUCTIVITY; ELECTRIC CURRENTS; ELECTRIC FIELDS; ELECTRIC POTENTIAL; ELECTRON GAS; ELECTRONS; HALL EFFECT; L-S COUPLING; MODULATION; SPIN; SPIN ORIENTATION; TIME DEPENDENCE