T-shaped ballistic spin filter

We propose a semiconductor structure that can filter electron spin without using external magnetic fields. The structure consists of a T-shaped quasi- one-dimensional channel and an electrode placed near the channel intersecti on to control the spin-orbit interaction for electrons. Our calculations de monstrate that the proposed device can redirect electrons with opposite spi ns from an unpolarized source to left and right output leads, respectively, and, thus, serve as a spin filter. When the incident electron energy is in resonance with the quasilocalized zero-dimensional states at the intersect ion, polarization of the transmitted fluxes approaches 100%. (C) 2001 Ameri can Institute of Physics.