Infrared spin orientation and spin-galvanic effect in semiconductor heterostructures

It is shown that a homogeneous spin-polarized electron gas in semiconductor heterostructures can drive an electric current. Here we report on this spin-galvanic effect where the spin polarization has been achieved by optical orientation applying circularly polarized far-infrared laser radiation. The microscopic origin-of the effect is an inherent asymmetry of spin-flip scattering.