Coulomb drag in parallel quantum dotsV. Moldoveanu1 and B. Tanatar2
1 National Institute of Materials Physics - P.O. Box MG-7, 077125 Bucharest-Magurele, Romania, EU
2 Department of Physics, Bilkent University - Bilkent, 06800 Ankara, Turkey
received 26 March 2009; accepted in final form 2 June 2009; published June 2009
published online 9 July 2009
We study theoretically the electronic transport in parallel few-level quantum dots in the presence of both intradot and interdot long-range Coulomb interaction. Each dot is connected to two leads and the steady-state currents are calculated within the Keldysh formalism using the random-phase approximation for the interacting Green functions. Due to the momentum transfer between the two systems it is possible to get a nonvanishing current through an unbiased Coulomb-blockaded dot, if the other dot is set in the nonlinear transport regime. The transitions between the levels of the passive dot reduce the drag current and lead to negative differential conductance. We also discuss the dependence on temperature and the role of the lead-dot coupling.
73.23.Hk - Coulomb blockade; single-electron tunneling.
85.35.Ds - Quantum interference devices.
85.35.Be - Quantum well devices (quantum dots, quantum wires, etc.).
© EPLA 2009