Quantization accuracy of the acoustoelectric current

By deriving analytical formulae for the quantization accuracy of the acoustoelectric current, we reveal that: (1) the flatness of the current plateau for the typical present devices has reached the theoretical limit of about 100 ppm over a 1/1000 change of the gate voltage; (2) increasing the transport channel length, and counterintuitively, increasing the acoustic wavelength as well, would improve the quantization accuracy, and very promisingly up to 0.01 ppm as required for a quantum current standard.