Charge conveyance and nonlinear acoustoelectric phenomena for intense surface acoustic waves on a semiconductor quantum well

The combination of semiconductor quantum well structures and strongly piezoelectric crystals leads to a system in which surface acoustic waves with very large amplitudes can interact with charge carriers in the well. The surface acoustic wave induces a dynamic lateral superlattice potential in the plane of the quantum well which is strong enough to spatially break up a two-dimensional electron system into moving wires of trapped charge. This transition is manifested in an increase of the electron transport velocity with sound amplitude, eventually reaching the sound velocity. The sound absorption by the electron system then becomes governed by nonlinearities and is strongly reduced. We study the transition from the linear towards the strongly nonlinear regime of interaction and present a theoretical description of such phenomena in a 2D system.