ELECTRIC-FIELD DOMAIN FORMATION AND MULTISTABILITY IN SEMICONDUCTOR MULTIPLE-QUANTUM WELLS IN THE PRESENCE OF THZ RADIATION

We propose a self-consistent microscopic model of vertical sequential tunneling through multiple quantum wells in the presence of THz radiat ion. The model considers the Coulomb interaction in a mean field appro ximation. We analyze the current density through a double quantum well and a superlattice and study the formation of electric field domains in the presence of THz radiation and the appearance of new multistabil ity regions, both caused by the combined effect of the strong nonlinea rity coming from the Coulomb interaction and the new photon-assisted t unneling channels. We show how the electric field domains can be suppo rted by the virtual photonic sidebands due to multiple photon emission and absorption.