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arXiv · 1802.02484

Dark states in spin-polarized transport through triple quantum dot molecules

Kacper Wrześniewski·Ireneusz Weymann
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Abstract

We study the spin-polarized transport through a triple quantum dot molecule weakly coupled to ferromagnetic leads. The analysis is performed by means of the real-time diagrammatic technique including up to the second order of perturbation expansion with respect to the tunnel coupling. The emphasis is put on the impact of dark states on spin-resolved transport characteristics. It is shown that the interplay of coherent population trapping and cotunneling processes results in a highly nontrivial behavior of the tunnel magnetoresistance, which can take negative values. Moreover, a super-Poissonian shot noise is found in transport regimes where the current is blocked by the formation of dark states, which can be additionally enhanced by spin-dependence of tunneling processes, depending on magnetic configuration of the device. The mechanisms leading to those effects are thoroughly discussed.

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Kacper Wrześniewski, Ireneusz Weymann. 2018-02-07. Dark states in spin-polarized transport through triple quantum dot molecules. https://doi.org/10.1103/physrevb.97.075425

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