Single-electron acoustic charge transport by two counterpropagating surface acoustic wave beams

A powerful surface acoustic wave can transport charge along a quasi-one-dim ensional channel defined in a piezoelectric semiconductor in packets confin ed to the minima of the wave's electrostatic potential. The interaction bet ween electrons can suppress fluctuation in the number of electrons in a pac ket, resulting in a current that is proportional to the surface acoustic wa ve (SAW) frequency. This effect has been observed experimentally and is pre sently being considered as a possible route towards a standard of electric current. Here we present further study of this acoustic charge transport. T he main finding is that a weak counterpropagating SAW beam can be used to i mprove the precision of the current delivered by the device. [S0163-1829(99 )02431-5].