The Effect of a Magnetic Field on the Acoustoelectric current in a Narrow Channel

TL;DR

This study investigates how a perpendicular magnetic field influences the quantized acoustoelectric current in a narrow GaAs channel, revealing oscillations and tunneling effects explained through a quantum dot model.

Contribution

It provides a qualitative explanation of the steplike current behavior and oscillations under magnetic fields using a transfer Hamiltonian approach.

Findings

Observation of commensurability oscillations in quantized current

Identification of tunneling into the 2D region as a key mechanism

Qualitative explanation of current steps and oscillations

Abstract

The effect of a perpendicular magnetic field on the quantized current induced by a surface acoustic wave in a quasi-1D channel is studied. The channel has been produced experimentally in a GaAs heterostructure by shallow etching techniques and by the application of a negative gate voltage to Schottky split gates. Commensurability oscillations of the quantized current in this constriction have been observed in the interval of current between quantized plateaus. The results can be understood in terms of a moving quantum dot with the electron in the dot tunneling into the adjacent two-dimensional region. The goal is to explain qualitatively the mechanism for the steplike nature of the acoustoelectric current as a function of gate voltage and the oscillations when a magnetic field is applied. A transfer Hamiltonian formalism is employed.