Balance equation approach to charge transport and spin polarization in spin-orbit coupled two-dimensional electron systems

The charge mobility and current-induced spin polarization in a spin-orbit coupled two-dimensional electron system are studied using a nonparabolic balance equation approach with impurity and phonon scatterings. For remote and/or background impurity and realistic phonon scatterings, the electron mobilities are found to depend on the Rashba coupling constant and the nonlinear dependence of spin polarization on the coupling strength is also observed, in contrast to the case of short-range impurity scattering. In the nonlinear case, a strong electric field makes the nonzero component of the spin polarization saturate and the Rashba spin-orbit coupling enhances the cooling of electron temperature.