Nonmagnetic spin-field-effect transistor

We propose a spin-field-effect transistor based on a semiconductor quantum wire with spin-orbit coupling and normal electrical contacts, instead of the ferromagnetic contacts required in the Datta and Das spin-field-effect transistor. The spin of electrons can be completely polarized and detected by manipulating and detecting the orbital wave-function using the spin-orbit coupling. The central spin-orbit coupled region consists of two segments with different strengths of Rashba spin-orbit coupling alpha(1) and alpha(2), respectively. The conductance is nearly 1 for the case of alpha(2) = alpha(1) and 0 for alpha(2) = -alpha(1) in a wide energy range. The device can work as a nonmagnetic spin transistor, which can have important applications in spintronics. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4747494]