Electron transport driven by moving quantum dots in distant quantum point contacts
Department of Physics, Sichuan University - Chengdu 610064, China
2 National Institute of Measurement and Testing Technology - Chengdu 610021, China
Accepted: 31 October 2011
Using moving quantum dots defined by surface acoustic waves that allow us to observe correlated electron transport in micron-separated quantum point contacts (QPCs), we present evidence for electron transport efficiency change that occurs where the coupling between these QPCs is provided by a region of two-dimensional electron gas rather than a static quantum dot. It is found that, when the latter QPC is set beyond conductance pinch-off, sweeping the first QPC, the acoustoelectric current shows a triangular-shaped peak. On the other hand, as the first QPC defines the entrance barrier by applying a fixed voltage and the voltage applied to the latter QPC is varied, we observe a resonant peak in the acoustoelectric current that is correlated to the point where the swept-QPC conductance nearly pinches off. From a study of the experimental characteristics, we suggest that they may be associated with the energy level rearrangement in the multi-QPC system as a result of charging up by dynamic quantum dots with their neighboring two-dimensional electron gas reservoirs.
PACS: 77.65.Dq – Acoustoelectric effects and surface acoustic waves (SAW) in piezoelectrics / 73.63.Kv – Quantum dots / 05.60.Gg – Quantum transport
© EPLA, 2011