Intense terahertz laser fields on a two-dimensional hole gas with Rashba spin–orbit coupling

We investigate the influence on the density of states and the density of spin polarization for a two-dimensional hole gas with Rashba spin–orbit coupling under intense terahertz laser fields. Via Floquet theorem, we solve the time-dependent Schrödinger equation and calculate these densities. It is shown that a terahertz magnetic moment can be induced for low hole concentration. Different from the electron case, the induced magnetic moment is quite anisotropic due to the anisotropic spin–orbit coupling. Both the amplitude and the direction of the magnetic moment depend on the direction of the terahertz field. We further point out that for high hole concentration, the magnetic moment becomes very small due to the interference caused by the momentum dependence of the spin–orbit coupling. This effect also appears in two-dimensional electron systems.