The spin Hall effect

In metallic systems with spin-orbit coupling a longitudinal charge current may generate a transverse pure spin current; vice-versa an injected pure spin current may result in a transverse charge current. Such direct and inverse spin Hall effects share the same microscopic origin: intrinsic band/device structure properties, external factors such as impurities, or a combination of both. They allow all-electrical manipulation of the electronic spin degrees of freedom,i.e. without magnetic elements, and their transverse nature makes them potentially dissipationless. It is customary to talk of spin Hall effects in plural form, referring to a group of related phenomena typical of spin-orbit coupled systems of lowered symmetry.