Dynamic spin-polarized shot noise in a quantum dot coupled to ferromagnetic terminals under the perturbation of ac fields |
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Authors: | H-K Zhao L-L Zhao and J Wang |
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Institution: | 1.Key Laboratory of Cluster Science of Ministry of Education,Beijing,P.R. China;2.Department of Physics,Beijing Institute of Technology,Beijing,P.R. China;3.Department of Physics,The University of Hong Kong,Hong Kong,P.R. China |
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Abstract: | We have investigated the shot noise in the mesoscopic system
composed of a quantum dot (QD) coupled to ferromagnetic terminals
under the perturbation of ac fields. The shot noise has been derived
using the nonequilibrium Green's function (NGF) technique to
describe the spin polarization effect along with photon absorption
and emission processes in the Coulomb blockade regime. We have
examined the influence of spin polarization on the shot noise under
the perturbation of ac fields in the nonadiabatic regime.
The Coulomb blockade effect results
in the modification of shot noise compared with the noninteracting
case. The spin orientation contributes a spin valve effect for
controlling electron tunnelling through this QD, and different
resonant forms appear around the Coulomb blockade channel. The
photon-assisted spin-splitting and spin-polarization effect
contributes a photon-assisted spin valve to adjust the electron
tunnelling current and shot noise. The spin-polarization effect
varies the value of the Fano factor. However, it does not change
the noise type from sub-Poissonian to super-Poissonian. |
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Keywords: | |
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