Issue
EPL
Volume 87, Number 1, July 2009
Article Number 17001
Number of page(s) 5
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
DOI http://dx.doi.org/10.1209/0295-5075/87/17001
Published online 15 July 2009
EPL, 87 (2009) 17001
DOI: 10.1209/0295-5075/87/17001

Resonant-tunneling–based spin ratchets

Matthias Scheid, Andreas Lassl and Klaus Richter

Institut für Theoretische Physik, Universität Regensburg - 93040 Regensburg, Germany, EU

Matthias.Scheid@physik.uni-r.de

received 9 April 2009; accepted in final form 12 June 2009; published July 2009
published online 15 July 2009

Abstract
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.

PACS
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