433 research outputs found
Magnification of spin Hall effect in bilayer electron gas
Spin transport properties of a coupled bilayer electron gas with Rashba
spin-orbit coupling are studied. The definition of the spin currents in each
layer as well as the corresponding continuity-like equations in the bilayer
system are given. The curves of the spin Hall conductivities obtained in each
layer exhibit sharp cusps around a particular value of the tunnelling strength
and the conductivities undergo sign changes across this point. Our
investigation on the impurity effect manifests that an arbitrarily small
concentration of nonmagnetic impurities does not suppress the spin Hall
conductivity to zero in the bilayer system. Based on these features, an
experimental scheme is suggested to detect a magnification of the spin Hall
effect.Comment: Revtex 10 pages, 4 figures; largely extended versio
Understanding spin transport from the motion in SU(2)U(1) fields
Starting from a continuum constituted by charged tops, we formulate the
classical counterpart of a previously obtained covariant continuity-like
equation for the spin current. Such a formulism provides an intuitive picture
to elucidate the non-conservation of the spin current and to interpret the
condition for the emergence of an infinite spin relaxation time. It also
facilitates the discussion on the spin precession in a one-dimensional quantum
wire with Dresselhaus and Rashba spin-orbit couplings. Furthermore, we derive
the diffusion equations for both the charge and spin densities and find that
they couple to each other due to the Zitterbewegung.Comment: 6 pages, 4 figures; this is the extended version of
Xiv:cond-mat/0608303 to publish in PR
Globular Adiponectin Inhibits the Apoptosis of Mesenchymal Stem Cells Induced by Hypoxia and Serum Deprivation via the AdipoR1-Mediated Pathway
Correlation between lasing and transport properties in a quantum dot-resonator system
We study a double quantum dot system coherently coupled to an electromagnetic
resonator. By suitably biasing the system, a population inversion can be
created between the dot levels. The resulting lasing state exists within a
narrow resonance window, where the transport current correlates with the lasing
state. It allows probing the lasing state via a current measurement. Moreover,
the resulting narrow current peak opens perspective for applications of the
setup for high resolution measurements.Comment: 4 pages, 4 figures; submitted to "Journal of Physics: Conference
Series
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