Resonant manipulation of spin current with a double-barrier structure

In this work, we consider a Rashba-type narrow channel consisting of two AC-biased finger-gates (FG) that orient perpendicularly and lie above the narrow channel. It is shown recently that such a gate configuration can give rise to dc spin current [1]. The dc spin current can be greatly enhanced by an optimal choice of the separation between the FGs. With the introduction of a double-barrier structure in between the FGs, we can explore the interplay between the dc spin current generation and the resonant levels in the double-barrier structure. Our results show that the direction of the dc spin current can be monitored by the chemical potential alone. No charge current, however, is generated in this configuration. [1] L. Y. Wang, C. S. Tang, and C. S. Chu, cond-mat/0409291