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 $\omega_{ c}\tau_{ \ast}\lesssim1$ (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.
Categories: cond-mat.mes-hall