SEQUENTIAL TUNNELING CURRENT THROUGH SEMICONDUCTOR SUPERLATTICES UNDER INTENSE THZ RADIATION

Recent transport measurements in GaAs-GaAlAs superlattices under THz r adiation show evidence of dynamical localization and electron pumping in the opposite direction to the de bias in the linear response regime . The ac field induces absorption and emission processes in the multiw ell structure which assist the tunnel and which are reflected as new f eatures in the current density. A calculation within the framework of the Bardeen Hamiltonian has been performed to evaluate the tunneling c urrent through the superlattice in the presence of an ac field, By mea ns of this model these new features are reproduced in the current whic h can be explained in terms of the new induced tunneling channels and of the charge occupation in the wells. (C) 1997 American Institute of Physics.