The structural parameter optimization of interdigital transducer in single electron transport devices

摘要

We investigate the influence of the interdigital transducer (IDT) structure on the amplitude of the surface acoustic wave (SAW) in a SAW device. The SAW amplitude at the entrance of the quantum point contact (QPC) is obtained by using coupling-of-modes theory and p-matrix method. The calculated results indicate that a device with an IDT with a relatively small aperture, large pairs of IDT fingers, and short distance between the active IDT and the QPC, the SAW amplitude is typically enhanced under the same radio frequency (rf) power. Based on these results, we design the corresponding SAW devices, and good agreement is achieved between the experimental data and the numerical results. In experiment, for the devices with optimal IDTs, the rf powers required to observe the quantized acoustoelectric current are reduced; correspondingly, the rf heating effect is reduced. Most importantly, the improvement of the accuracy of the quantized plateau is achieved.