Resonant-tunneling–based spin ratchetsMatthias Scheid, Andreas Lassl and Klaus Richter
Institut für Theoretische Physik, Universität Regensburg - 93040 Regensburg, Germany, EU
received 9 April 2009; accepted in final form 12 June 2009; published July 2009
published online 15 July 2009
We outline a generic ratchet mechanism for creating directed spin-polarized currents in ac-driven double-well or double-dot structures by employing resonant spin transfer through the system engineered by local external magnetic fields. We show its applicability to semiconductor nanostructures by considering coherent transport through two coupled lateral quantum dots, where the energy levels of the two dots exhibit opposite Zeeman spin splitting. We perform numerical quantum-mechanical calculations for the I-V characteristics of this system in the nonlinear regime, which requires a self-consistent treatment of the charge redistribution due to the applied finite bias. We show that this setting enables nonzero averaged net spin currents in the absence of net charge transport.
72.25.Dc - Spin polarized transport in semiconductors.
73.40.Ei - Rectification.
71.70.Ej - Spin-orbit coupling, Zeeman and Stark splitting, Jahn-Teller effect.
© EPLA 2009