A single-spin-current thermal generator

We theoretically propose a single-spin-current thermal generator consisting of a Rashba quantum dot (QD), one hot electrode and two cold electrodes. The Rashba QD is directly coupled to the three electrodes, and there exists a bridge channel between the two cold electrodes. Our results show the QD device can be used to generate pure spin-up or spin-down currents in cold electrodes in the absence of bias voltages and magnetic materials. The underlying reason is a cooperative effect of the spin-dependent quantum interference effects originating from Rashba spin-orbit interaction in the QD and temperature gradients among the three electrodes. The working conditions for the single-spin-current thermal generator are also clearly presented. Moreover, we also find that the device can be converted from n-type to p-type or vice versa by a gate voltage. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4739292]