Electronic subband structure in two-dimensional electron gases under intense laser radiations

We present a theoretical study on the influence of intense terahertz (THz) electromagnetic (EM) radiations on the electronic structures in a modulation-doped two-dimensional (2D) semiconductor system. We find that in the presence of a THz EM radiation field polarised linearly along the 2D-plane of a 2D electron gas (2DEG), the electron density of states will be modified strongly by the intensity and the frequency of the radiation field. As a consequence, the Fermi-energy and the electron density in the system will be affected markedly by the EM radiations. The results have indicated that the photon modified electronic subband structure in a 2DEG device can be observed by using the recently developed free-electron laser sources. (C) 1998 Elsevier Science B.V. All rights reserved.