摘要
We report on studies of the decoherence processes of a ballistic quantum interferometer subjected to a radio-frequency (RF) electromagnetic (EM) field and a surface acoustic wave (SAW). The device consists of an Aharonov-Bohm (AB) ring sandwiched between two interdigital transducers (IDTs), where the AB ring serves as a phase sensor and the IDTs function as a controlled source of environmental noise. By employing the IDTs with an RF-EM field to launch a SAW train through the ring, we extract the decoherence rate Gamma phi from the AB oscillation amplitude and investigate the dephasing process through the RF power Prf dependence of Gamma phi, the electronic temperature Ts, and acoustoelectric current Iae spectrum. Our data reveal that the bandwidthnarrowing feature caused by Bragg reflections of the SAW is consistently found in the spectra of phi 0, Ts, and Iae, suggesting that the piezoelectric field is the dominant EM field contributing to decoherence. At the resonance frequency, the decoherence rate follows P1/5 rf dependence due to thermal fluctuation of the alternating electric current by the EM field. At the off-resonance condition, we identify that the asymmetric Gamma 0 spectrum is induced by the crosstalk of SAW interference under the influence of a weak Prf. Furthermore, we find the optimal conditions for operating the SAW to minimize dephasing without thermal heating. The underlying mechanism responsible for the decoherence is attributed to the enhancement of charge-charge interactions in the presence of the EM field and the SAW. These findings are crucial for the development of quantum electronic devices leveraging SAW technology.