Screening, nonadiabaticity, and quantized acoustoelectric current

TL;DR

This paper presents a theoretical study of quantized single-electron transport driven by surface acoustic waves, highlighting how Coulomb interactions and nonadiabatic effects influence the precision of acoustoelectric current quantization.

Contribution

It introduces a model accounting for Coulomb interactions and nonadiabaticity, explaining the limitations on quantization accuracy in acoustoelectric current transport.

Findings

Coulomb interactions cause rapid decay of tunneling coupling.

Decay time scale controls plateau transition widths.

Limits the accuracy of current quantization at low temperatures.

Abstract

Quantized single-electron transport driven by surface acoustic waves (SAW) through a pinched-off narrow constriction is studied theoretically. Long-range Coulomb interaction causes the tunneling coupling between the two-dimensional electron gas (2DEG) and the moving minimum of the SAW-induced potential to decay rapidly with time. The energy scale, associated with the characteristic time of this decay, controls both the width of the transition regions between the plateaus and the slope of the plateaus. This sets a limit for the accuracy of the quantization of acoustoelectric current at low temperature.