Abstract
The full counting statistics of electron transport through a quantum dot (QD) doped with a single magnetic impurity weakly coupled to one ferromagnetic (F) and one normal-metal lead (N) is studied based on an efficient particle-number-resolved master equation. We demonstrate that the current noise properties depend sensitively on whether the source-electrode is the ferromagnetic lead and the type of exchange coupling between the conduction electron and magnetic impurity spin. For the F-QD-N system, namely, the ferromagnetic lead as source electrode and the normal-metal lead as drain one, the super-Poissonian noise in the anti-ferromagnetic coupling case can appear; whereas for the ferromagnetic coupling case the super-Poissonian noise does not appear. As for the N-QD-F system, the super-Poissonian noise in the ferromagnetic coupling case can appear in a relatively large bias voltage range; while for the anti-ferromagnetic coupling case, the super-Poissonian noise appears only in a relatively small bias voltage range. These super-Poissonian noise characteristics can be used to reveal the type of exchange coupling between the conduction electron and magnetic impurity spin, and can be qualitatively attributed to the spin-blockade mechanism and the effective competition between fast and slow transport channels.
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