Adiabatic Spin Pumping with Quantum Dots
Electronic transport in mesoscopic systems has been intensively studied for more the last three decades. While there is a substantial understanding of the stationary regime, much less is know about phase-coherent nonequilibrium transport when pulses or ac perturbations are used to drive electrons at low temperatures and at small length scales. However, about 20 years ago Thouless proposed to drive nondissipative currents in quantum systems by applying simultaneously two phase-locked external perturbations. The so-called adiabatic pumping mechanism has been revived in the last few years, both theoretically and experimentally, in part because of the development of lateral semiconductor quantum dots. Here we will explain how open dots can be used to create spin-polarized currents with little or no net charge transfer. The pure spin pump we propose is the analog of a charge battery in conventional electronics and may provide a needed circuit element for spin-based electronics. We will also discuss other relevant issues such as rectification and decoherence and point out possible extensions of the mechanism to closed dots.
KeywordsPure Spin Spin Component Spin Current Phase Coherence Zeeman Splitting
I am grateful to C. Chamon, C. Lewenkopf, C. Marcus, and M. Martínez-Mares for fruitful collaborations on this subject. The material presented here is based on published work we have co-authored. I also would like to thank P. Brouwer, B. Reulet, P. Sharma, and S. Watson for useful discussions.
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