Quantized charge pumping through a quantum dot by surface acoustic waves

TL;DR

This paper demonstrates quantized charge pumping in a quantum dot using surface acoustic waves, achieving precise control of single-electron transport at gigahertz frequencies.

Contribution

It introduces a method to realize quantized charge pumping through a quantum dot driven by surface acoustic waves, with detailed experimental validation.

Findings

Quantized current observed at multiple integer values of electrons per cycle

Pumping frequency of 3 GHz achieved

Resonance with electronic states controls electron transport

Abstract

We present a realization of quantized charge pumping. A lateral quantum dot is defined by metallic split gates in a GaAs/AlGaAs heterostructure. A surface acoustic wave whose wavelength is twice the dot length is used to pump single electrons through the dot at a frequency f=3GHz. The pumped current shows a regular pattern of quantization at values I=nef over a range of gate voltage and wave amplitude settings. The observed values of n, the number of electrons transported per wave cycle, are determined by the number of electronic states in the quantum dot brought into resonance with the fermi level of the electron reservoirs during the pumping cycle.