Commensurability oscillations in the SAW induced acousto-electric effect in a 2DEG

Abstract

We study the acousto-electric (AE) effect generated by surface acoustic waves (SAW) in a high mobility 2D electron gas (2DEG) with isotropic and especially small-angle impurity scattering. In both cases the acousto-electric effect exhibits Weiss oscillations periodic in $B^{-1}$ due to the commensurability of the SAW period with the size of the cyclotron orbit and resonances at the SAW frequency $\omega =k{\omega }_c$ multiple of the cyclotron frequency. We describe how oscillations in the acousto-electric effect are damped in low fields where ${\omega }_c{\tau }_{\ast }\lesssim 1$ (with the time scale ${\tau }_{\ast }$ dependent on the type of scattering) and find its non-oscillatory part which remains finite to the lowest fields.

4 pages, 0 figures. Submitted to PRB