Enhanced quantized current driven by surface acoustic waves

We present the experimental realization of different approaches to increase the amount of quantized current which is driven by surface acoustic waves through split-gate structures in a two-dimensional electron gas. Samples with driving frequencies of up to 4.7 GHz have been fabricated without a deterioration of the precision of the current steps, and a parallelization of two channels with correspondingly doubled current values have been achieved. We discuss theoretical and technological limitations of these approaches for metrological applications as well as for quantum logics. (C) 2000 American Institute of Physics. [S0003-6951(00)05442-5].