High-frequency nonlinear response of double-well nanostructures

A theory on the high-frequency nonlinear response of a double-well nanostructure in a constant electric field has been developed. Such a structure is the next simplest in form after a single-well structure (a resonant-tunnel diode) but less complex than a superlattice with a one-band "Stark ladder." By solving the Schrodinger equation numerically, the polarization current over wide ranges of frequencies and fields, including high fields, is found for model and real structures. It is shown that the response of a double-well nanostructure is much higher (by one or two orders of magnitude) than that of a resonant-tunnel diode. A new optimal mode of generation, similar to that based on interlevel transitions in a coherent laser, is predicted. (c) 2005 Pleiades Publishing, Inc.