Spin relaxation in the channel of a spin field-effect transistor

We examine the major spin relaxation mechanism (D'yakonov-Perel') in the channel of a spin field-effect transistor (SPINFET) and show analytically that it can be completely eliminated if the channel is a quantum wire and transport is strictly single moded (only the lowest subband is occupied). Single-moded transport also produces the largest "on" to "off" conductance ratio and the largest transconductance of the transistor.