Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 11: Transport: Nanoelectronics I - Quantum Dots and Wires, Point Contacts 2
TT 11.3: Vortrag
Montag, 23. März 2009, 14:30–14:45, HSZ 301
Charge and spin pumping through quantum dots beyond the adiabatic regime — •Fabio Cavaliere1, Michele Governale2, and Jürgen König2 — 1Dipartimento di Fisica, Università di Genova, LAMIA CNR-INFM, Via Dodecaneso 33, 16146 Genova, Italy — 2Theoretische Physik, Universität Duisburg-Essen, 47048 Duisburg, Germany
We study charge and spin pumping in an interacting quantum dot connected to normal or ferromagnetic leads, beyond the adiabatic regime. We employ a systematic expansion of the pumped currents in both frequency and tunneling strength. Going beyond the adiabatic regime has important consequences on the pumping characteristics. In the case of normal leads, the pumped current exhibits a sub-linear increase for increasing pumping frequency and its dependence on the phase-difference between the pumping field deviates from that of the adiabatic regime. In the ferromagnetic case, spin and charge currents behave differently as a function of the phase difference, allowing to obtain pure spin pumping without net charge transfer, in sharp contrast to the adiabatic regime [1].
[1] J. Splettstoesser, M. Governale, and J. König, Phys. Rev. B 77, 195320 (2008).