The quantized acoustoelectric current for different lengths of a quasi-one-dimensional channel

A length-dependent investigation of quantized acoustoelectric current in shallow-etched constrictions is reported. We analyze the quantized precision for different channel lengths. The study indicates that there is a significant effect of the channel length on the quality of quantized current. As the channel length becomes too short or too long, poor plateaus are shown, and some reasonable explanations about this behavior are presented. Furthermore, obvious deviations from the ideal quantized value are observed for long constrictions in our experiments, and a mechanism which is different from previous discussions is put forward to be responsible for this behavior.