Effect of impurities in the channel of a spin field effect transistor (SPINFET)

We show that the conductance modulation of Spin Field Effect Transistors (SPINFET) is affected by a single (non-magnetic) impurity in the transistor´s channel. The extreme sensitivity of the amplitude and phase of the transistor´s conductance oscillations to the location of a single impurity in the channel is reminiscent of the phenomenon of universal conductance fluctuations in mesoscopic samples and is extremely problematic as far as device implementation is concerned.