Nonmagnetic spin-field-effect transistor

Abstract

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 α1 and α2, respectively. The conductance is nearly 1 for the case of α2=α1 and 0 for α2=−α1 in a wide energy range. The device can work as a nonmagnetic spin transistor, which can have important applications in spintronics.