Dark states in spin-polarized transport through triple quantum dot molecules
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.
Cite
@article{arxiv.1802.02484,
title = {Dark states in spin-polarized transport through triple quantum dot molecules},
author = {Kacper Wrześniewski and Ireneusz Weymann},
journal= {arXiv preprint arXiv:1802.02484},
year = {2018}
}