Spin-Transistor Action via Tunable Landau-Zener Transitions

Abstract

A Different Spin Transistor A typical transistor consists of a source and a drain; the current that makes it to the drain is controlled by applying voltage to the third terminal, called the gate. In spin-based electronics, where spin current is used instead of charge, the source and the drain are ferromagnetic materials connected by a narrow semiconducting channel. This design, however, suffers from low efficiency. Betthausen et al. (p. 324 ; see the Perspective by Žutić and Lee ) combined homogeneous and helical magnetic fields to change the orientation of the spin on its way to the drain, preserving spin information over distances many times the spin mean free path. The transistor is “on” when the transport is adiabatic—i.e., slow enough for the spin to be able to adapt to the local magnetic field—and “off” otherwise.