Spin blocking effect in symmetric double quantum well due to Rashba spin-orbit coupling*

We report a theoretical study of the spin-dependent electronic current flowing laterally through the In$_{0.53}$Ga$_{0.47}$As/In$_{0.52}$Al$_{0.48}$As double quantum well (DQW) structure, where the values of the Rashba spin-orbit parameter $\alpha_{\rm R}$ are opposite in sign but equal in magnitude between the constituent quantum wells [1]. By tuning the channel length of DQW and the magnitude of the externally applied in-plane magnetic field, one can block the transmission of one spin (e.g., spin-up) component, enabling us to obtain a spin-polarized current. Our experimental progress toward realizing the proposed device is also reported [2]. [1] T. Matsuura, S. Faniel, N. Monta, and T. Koga, Physica E {\bf 42}, 2707 (2010). [2] T. Koga, T. Matsuura, S. Faniel, S. Souma, S. Mineshige, Y. Sekine, and H. Sugiyama, IEICE Trans. Electron. {\bf E95-C}, 770 (2012).