An Improved 2.5 GHz Electron Pump: Single-Electron Transport through Shallow-Etched Point Contacts Driven by Surface Acoustic Waves

We present an experimental study of a 2.5 GHz electron pump based on the quantized acoustoelectric current driven by surface acoustic waves through a shallow-etched point contact in a GaAs/AlGaAs heterostructure. At low temperatures and with an additional counter-propagating surface acoustic waves beam, up to n = 20 current plateaus at I = nef could be resolved, where n is an integer, e the electron charge, and f the surface acoustic waves frequency. In the best case the accuracy of the first plateau at 0.40 nA was estimated to be ΔI/I = ′25 ppm over 0.25 mV in gate voltage, which is better than previous results.