It is shown that a finite spin-Hall current can be induced by applying an in-plane magnetic field in a diffusive two-dimensional electron system with the Rashba and Dresselhaus spin-orbit couplings subjected to a dc electric field. The spin-Hall conductivity depends not only on the strength and direction of the magnetic field, but also strongly depends on the form of the scattering potential. It can be negative or positive in the case of remote impurity scattering, but essentially positive in the case of short-range scattering.

We investigate effects of intense terahertz ͑THz͒ radiations on a clean In 1−x Ga x As-based two-dimensional electron gas with Rashba spin-orbit coupling. It is found that the density of states and the Fermi energy of this system are modulated by the THz radiation and a time-dependent spin-Hall current ͑SHC͒ is induced. The SHC oscillates at the frequency of THz field with an amplitude increasing with reducing radiation frequency and increasing Rashba spin-orbit interaction ͑SOI͒ strength. On the other hand, at fixed radiation frequency and SOI coupling strength the amplitude of the induced SHC first increases and, after reaching a maximum, decreases with continuous growth of the radiation strength. These results demonstrate the possibility of realizing an efficient optical control of the spintronic devices.