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.Comment: 3pages, 4eps-figure

We investigated the local potential distribution over gated double-bridge structures patterned on GaAs/GaAlAs heterostructures. The current and potential distribution over the gated double-bridge devices was measured for several sets of filling factors below the two gates and in the ungated region. The fractions of the Hall voltage and the bridge currents experimentally obtained for both bridges correspond exactly to the values predicted by model calculations. Depending on the choice of the filling factor distribution, particular sequences of voltage steps across the bridges can be generated. This might be of some interest for metrological applications. We show that the current and voltage distribution for the double-gate device can be calculated using the edge-current picture. However, it is also shown that exactly the same results can be obtained using a local model in which edge currents are not considered. This has consequences concerning the open question of the extent to which the existence of edge currents in quantizing magnetic fields affects magnetotransport data at integer filling factors.

The surface acoustic wave (SAW) induced quantized transport of electrons [l] has been studied in an extended frequency range. Using electron beam lithography, Interdigital Transducers (IDTs) of different types have been designed and fabricated for frequencies of up to 9 GHz. Successful operation of the devices has been possible up to 5 GHz.

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