Dresden 2011 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 43: TR: Nanoelectronics II - Spintronics and Magnetotransport 2 (jointly with HL and MA)
TT 43.2: Vortrag
Mittwoch, 16. März 2011, 19:15–19:30, HSZ 03
Adiabatic pumping through an interacting quantum dot with time-dependent magnetisation — •Nina Winkler1, Michele Governale2, and Jürgen König1 — 1Theoretische Physik and CeNIDE · Universität Duisburg-Essen — 2School of Chemical and Physical Sciences and MacDiarmid Institute for Advanced Materials and Nanotechnology · Victoria University of Wellington · New Zealand
We investigate adiabatic charge and spin transport through a system composed of a quantum dot with Coulomb interaction, weakly tunnel coupled to one normal and one ferromagnetic lead with time-dependent magnetisation.
Adiabatic pumping is typically studied in systems in which the properties of the scattering
region are changed, e.g. gate voltages to vary the tunnel couplings and the level position of the quantum dot.
In general, it is also possible to generate a current by varying in time the lead properties, e.g. the direction of the magnetisation solely [1].
We study the adiabatically pumped charge and spin current up to second order in the tunnel-coupling strength when pumping by varying the direction of the lead magnetisation periodically in time. To this aim, we extend a diagrammatic real-time approach for adiabatic pumping through quantum dots with ferromagnetic leads [2,3] to allow for time-dependent magnetisations. We perform a systematic expansion in both frequency and tunnel-coupling strength, treating the on-site Coulomb interaction on the quantum dot exactly.
[ 1] M.V. Costache et al. , Phys. Rev. Lett. 97, 216603 (2006).
[ 2] J. Splettstoesser et al. , Phys. Rev. B 74, 085305 (2006).
[ 3] J. Splettstoesser et al. , Phys. Rev. B 77, 195320 (2008).