The ABC of Aharonov Effects

An electron traveling through an electric field experiences, in its rest frame, a magnetic field that interacts with the electron’s magnetic moment. This interaction is the basis of spin-orbit coupling, which causes a splitting of the energies of electrons in atoms depending on their spin state. In the case of electrons traveling along an interface between two different semiconductors, the transition from one conduction-band energy to another manifests itself as a local electric field that gives rise to a spin-orbit interaction. Here, the resulting momentumdependent spin splitting is known as the Rashba effect [1]. Because the magnitude of the effect depends on the junction parameters and can be controlled by an external electric field, the Rashba interaction offers a promising tool for “spin-orbitronics,” in which spins can be manipulated through purely electrical mechanisms.