Resonant spin polarization and spin current in a two-dimensional electron gas

We study the spin polarization and its associated spin-Hall current due to electric-dipole-induced spin resonance in disordered two-dimensional electron systems. We show that the disorder-induced damping of the resonant spin polarization can be strongly reduced by an optimal field configuration that exploits the interference between the Rashba and Dresselhaus spin-orbit interactions. This leads to a striking enhancement of the spin susceptibility while the spin-Hall current vanishes at the same time. We give an interpretation of the spin current in geometrical terms which are associated with the trajectories the polarization describes in spin space.