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 43.1: Vortrag

Mittwoch, 16. März 2011, 19:00–19:15, HSZ 03

Spin polarized transport in metallic magnetic single electron transistors — •Stephan Lindebaum and Jürgen König — Theoretische Physik, Universität Duisburg-Essen and CeNIDE, 47048 Duisburg, Germany

We study the electronic transport through a ferromagnetic single electron transistor (fmSET), realized by a metallic island weakly coupled to two ferromagnetic leads. The polarization directions of the ferromagnets enclose a noncollinear angle. In the considered system, charging and spin effects play an important role. For example the accumulated spin on the island precesses due to a many-body exchange field, which arises as a consequence of virtual tunneling processes from the metallic island to the magnetic leads in presence of strong Coulomb interaction on the central electrode.

To analyze the system we perform a perturbative analysis of the transport properties up to first order in the tunnel-coupling strength, but without doing any approximation for the Coulomb charging energy. A diagrammatic real-time transport theory enables us to derive kinetic equations for the island charge and spin degrees of freedom.

The theory covers both the linear and nonlinear transport regimes. The electric current through the fmSET and its conductance are analyzed in detail, while we explicitly investigate the influence of the exchange field on the transport parameters.