Different Quantization Mechanisms in Single-Electron Pumps Driven by Surface Acoustic Waves

P. Utkoa, K. Gloosb, J. Bindslev Hansenc, C.B. Sørensena and P.E. Lindelofa Nano-Science Center, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmarka bWihuri Physical Laboratory, Department of Physics, University of Turku, 20014 Turku, Finland cDepartment of Physics, Technical University of Denmark, 2800 Lyngby, Denmark

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Received: 17 06 2006;

We have studied the acoustoelectric current in single-electron pumps driven by surface acoustic waves. We have found that in certain parameter ranges two different sets of quantized steps dominate the acoustoelectric current versus gate-voltage characteristics. In some cases, both types of quantized steps appear simultaneously though at different current values, as if they were superposed on each other. This could indicate two independent quantization mechanisms for the acoustoelectric current.

DOI: 10.12693/APhysPolA.110.403 PACS numbers: 73.23.-b, 72.50.+b, 73.21.La