Berlin 2012 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 101: Transport: Nanoelectronics II - Spintronics and Magnetotransport (jointly with TT, MA)
HL 101.5: Talk
Friday, March 30, 2012, 10:30–10:45, BH 243
Adiabatic pumping through an interacting quantum dot with spin-orbit coupling — •Stephan Rojek1, Jürgen König1, and Alexander Shnirman2 — 1Theoretische Physik, Universität Duisburg-Essen and CeNIDE, 47048 Duisburg, Germany — 2Institut für Theorie der Kondensierten Materie and DFG-Center for Functional Nanostructures (CFN), Universität Karlsruhe, 76128 Karlsruhe, Germany
We study adiabatic pumping through a two-level quantum dot coupled to two normal metallic leads in the presence of spin-orbit coupling. The variation of the two energy levels of the dot periodically in time leads to finite charge and spin currents.
We calculate the pumped charge and spin using a diagrammatic real-time approach [1]. Going beyond the limit of noninteracting electrons on the quantum dot [2], we study the situation of strong Coulomb interaction. In both limits of noninteracting and strongly interacting electrons, spin-orbit coupling provides the possibility for pure spin current. We introduce an isospin to describe the level degree of freedom. This isospin feels an exchange field similar to the exchange field in a quantum-dot spin valve. The exchange field originates form the Coulomb interaction and its strength is sensitive to the symmetry in the tunneling matrix elements.
New features concerning the pure spin pumping as well as the absolute pumped charge of the two-level quantum dot with spin-orbit coupling arises from the Coulomb interaction.
[1] J. Splettstoesser et al., Phys. Rev. B 74, 085305 (2006).
[2] V. Brosco et al., Phys. Rev. B 82, 041309(R) (2010).