Temporal and spatial structure of phonon flux and induced drag currents in two-dimensional gases of electrons

Abstract

We consider the response of a two-dimensional gas of electrons (2DEG) to pulsed beams of long-wavelength acoustic phonons in the time domain. The temporal and spatial structure of phonon fluxes is also studied. The results of computer experiments and numerical calculations, performed for 2D electrons lying on the (001) surface of a 2 mm thick GaAs platelet, indicate that for carefully chosen positions of 2D gas structure the induced drag current has the form of peaks of the opposite sign separated by a time interval approximately equal to 25 ns. These maxima are much stronger than the strongest amplitudes of current obtained in standard experiments on the integrated patterns of the drag currents. The spatial structure of these maxima indicates that by improving the time resolution one can work with quite large 2DEG structures. We expect that these strong phonon pulses can be used for studying nonequilibrium states 2D gases of carriers.