Giant Oscillations of Acoustoelectric Current in a Quantum Channel

TL;DR

This paper develops a detailed theoretical model explaining giant oscillations of acoustoelectric current observed in quantum channels, highlighting the interplay between energy-momentum conservation and Fermi level splitting.

Contribution

It provides a comprehensive theory of acoustoelectric current oscillations in quantum channels, extending previous qualitative explanations with detailed analysis and limiting cases.

Findings

Giant oscillations of acoustoelectric current are explained by energy-momentum conservation.

The theory accounts for finite temperature effects on Fermi level splitting.

Limiting cases of the oscillation behavior are analyzed.

Abstract

A theory of d.c. electric current induced in a quantum channel by a propagating surface acoustic wave (acoustoelectric current) is worked out. The first observation of the acoustoelectric current in such a situation was reported by J. M. Shilton et al., Journ. Phys. C (to be published). The authors observed a very specific behavior of the acoustoelectric current in a quasi-one-dimensional channel defined in a GaAs-AlGaAs heterostructure by a split-gate depletion -- giant oscillations as a function of the gate voltage. Such a behavior was qualitatively explained by an interplay between the energy-momentum conservation law for the electrons in the upper transverse mode with a finite temperature splitting of the Fermi level. In the present paper, a more detailed theory is developed, and important limiting cases are considered.