Spin interferometry with electrons in nanostructures: A road to spintronic devices

The wave nature of electrons in semiconductor nanostructures results in spatial interference effects similar to those exhibited by coherent light. The presence of spin-orbit coupling renders interference in spin space and in real space interdependent, making it possible to manipulate the electron's spin state by addressing its orbital degree of freedom. This suggests the utility of electronic analogs of optical interferometers as blueprints for new spintronics devices. We demonstrate the usefulness of this concept using the Mach-Zehnder interferometer as an example. Its spin-dependent analog realizes a spin-controlled field-effect transistor without magnetic contacts and may be used as a quantum logical gate.