Rashba spin-orbit-coupled two-dimensional electron gas under an intense terahertz field: Theoretical calculations

We investigate effects of intense terahertz (THz) radiations on a clean In1-xGaxAs-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 (SHC) 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 (SOI) 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.