Spin pumping and spin filtering in double quantum dots with time-dependent spin-orbit interactions

We propose a scheme of realizing both spin pumping and spin filtering in a double quantum dot with homogeneous Zeeman splittings in the presence of oscillating spin-orbit interactions. We find that a spin-polarized pumping current can be achieved by tuning the relative energies of the Zeeman-split levels of the dots. It is also found that a pure spin current can be generated at zero detuning, whose magnitude can be modulated by the external fields. At a certain constellation of system parameters, the pumping current can become almost fully spin-polarized. Therefore, it is possible to select a particular spin component of the current to be pumped from the left to the right lead. We finally give some discussions on the realization of the spin pumping and spin filtering effects. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3703567]