Spin currents in a normal two-dimensional electron gas in contact with a spin–orbitinteraction region

Abstract

Spin effects in a normal two-dimensional (2D) electron gas in lateral contact with a 2Dregion with spin–orbit interaction are studied. The peculiarity of this system is the presenceof spin-dependent scattering of electrons from the interface. This results in an equilibriumedge spin current and nontrivial spin responses to a particle current. We investigate thespatial distribution of the spin currents and spin density under non-equilibrium conditionscaused by a ballistic electron current flowing normal or parallel to the interface. Theparallel electron current is found to generate a spin density near the interface and tochange the edge spin current. The perpendicular electron current changes theedge spin current proportionally to the electron current and produces a bulkspin current penetrating deep into the normal region. This spin current has twocomponents, one of which is directed normal to the interface and polarized parallelto it, and the second is parallel to the interface and is polarized in the planeperpendicular to the contact line. Both spin currents have a high degree of polarization (∼40–60%).