Spin polarization in a T-shaped conductor induced by strong Rashba spin-orbit coupling

We investigate numerically the spin polarization of the current in the presence of Rashba spin-orbit interaction in a T-shaped conductor proposed by Kiselev and Kim [Appl. Phys. Lett. 78, 775 (2001)]. The recursive Green function method is used to calculate the three terminal spin-dependent transmission probabilities. We focus on single-channel transport and show that the spin polarization becomes nearly 100% with a conductance close to e²∕h for sufficiently strong spin-orbit coupling. This is interpreted by the fact that electrons with opposite spin states are deflected into an opposite terminal by the spin-dependent Lorentz force. The influence of the disorder on the predicted effect is also discussed. Cases for multichannel transport are studied in connection with experiments.