Full counting statistics of a quantum dot doped with a single magnetic impurity

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. C 2013 Author(s)

Negative differential conductance and super-Poissonian shot noise in single-molecule magnet junctions

“…2(f) , whereas for the QD system the super-Poissonian noise dose not appear 43 . This characteristic can be understood in terms of the effective competition between fast and slow transport channels 32 33 34 41 44 45 46 47 48 49 50 and the forming speed of the new correlated eigenstates 49 . The current magnitudes of the SMM transport channels can be expressed as 14 32 34 where C | n − 1, m ± 1/2〉,| n , m 〉 = |〈 n − 1, m ± 1/2| d σ | n , m 〉| 2 is a constant which related to the two SMM eigenstates but independent of the applied bias voltage, and P | n , m 〉 is the occupation probability of the SMM eigenstate | n , m 〉.…”

“…2(f), whereas for the QD system the super-Poissonian noise dose not appear [40]. This characteristic can be understood in terms of the effective competition between fast and slow transport channels [31-33, 39, 41-46] and the forming speed of the new correlated eigenstates [45]. The current magnitudes of the SMM transport channels can be expressed as [13,31,33]…”

Bounds on skewness and kurtosis of steady state currents

“…The first quantity measures the asymmetry of probability distribution while the second one -the weight of distribution tails. Such measures have been previously theoretically applied to investigate phenomena such as quantum interference [41][42][43], Kondo effect [44], non-Markovian effects [45], cotunneling [46], Andreev tunneling [47,48], spin blockade [49] or detector-induced backaction [50] in nanoelectronic systems. Most notably, in tunnel junctions the third cumulant of the charge current c q 3 has been found to be directly proportional to the mean current c q 1 = j q as c q 3 = e 2 c q 1 , where e is the particle effective charge.…”

Quantum Phase Coherence in Mesoscopic Transport Devices with Two-Particle Interaction

“…The new observation is demonstrated by the full counting statistics (FCS) for particle transport in mesoscopic systems. The FCS has attracted great attentions in recent years 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 since the intrinsic properties of the mesoscopic system can be identified by the high-order cumulants of electron correlation besides the average transport-current itself 32 . It is believed that the high-order cumulants are useful to detect the zeros of generating function 33 and the intrinsic multi-stability 34 .…”