Article

# Nonadiabatic generation of spin currents in a quantum ring with Rashba and Dresselhaus spin-orbit interactions

Journal of Physics Conference Series 09/2011; 338(1). DOI:10.1088/1742-6596/338/1/012013
Source: arXiv

ABSTRACT When subjected to a linearly polarized terahertz pulse, a mesoscopic ring
endowed with spin-orbit interaction (SOI) of the Rashba-Dresselhaus type
exhibits nonuniform azimuthal charge and spin distributions. Both types of SOI
couplings are considered linear in the electron momentum. Our results are
obtained within a formalism based on the equation of motion satisfied by the
density operator which is solved numerically for different values of the angle
$\phi$, the angle determining the polarization direction of the laser pulse.
Solutions thus obtained are later employed in determining the time-dependent
charge and spin currents, whose values are calculated in the stationary limit.
Both these currents exhibit an oscillatory behavior complicated in the case of
the spin current by a beating pattern. We explain this occurrence on account of
the two spin-orbit interactions which force the electron spin to oscillate
between the two spin quantization axes corresponding to Rashba and Dresselhaus
interactions. The oscillation frequencies are explained using the single
particle spectrum.

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