Spin polarization in a double-quantum dot interferometer with Rashba spinorbit interaction

We propose a spin device consisting of three normal metal leads and double quantum dots (QDs) with Rashba spin-orbit (RSO) interaction. On the basis of the nonequilibrium Keldysh Green's function technique, the spin-polarized currents flowing in different leads and spin accumulations in QDs are investigated. It is shown that the spin-polarized currents with opposite direction can be extracted into the left and right leads, respectively, due to the quantum interference between different channels. Moreover, the magnitude and direction of polarization can be modulated electrically by shifting the dots' levels and tuning the strength of the RSO interaction. The spin-polarized currents exhibit a 2 pi-periodic function with respect to phi(R). In addition, the direction of the spin accumulation in two dots is exactly opposite and its magnitude and direction can be easily controlled by tuning the levels.