The action on a two-dimensional electron gas (2DEG) by electric fields that
accompany surface acoustics waves (SAWs) propagating in GaAs-AlxGa1-xAs he
terostructures is typically negligible because of screening. In the quantum
Hall regime, the longitudinal conductivity of the 2DEG is nearly zero when
the Fermi level lies in the Landau gap. Consequently, the SAWs can build u
p electric fields that are strong enough to rake off mobile electrons. We d
emonstrate that inhomogeneous carrier distributions produced in the course
of photoionization of DX centers can be flattened out by applying the SAWs
in high magnetic fields. (C) 2000 American Institute of Physics. [S0003-695
1(00)01816-7].