Magnetoconductance switching in an array of oval quantum dots

TL;DR

This paper investigates how the geometry of oval quantum dots in a linear array influences magnetoconductance switching, demonstrating a low-field, geometry-dependent effect with potential experimental observability despite disorder effects.

Contribution

It introduces a method to optimize quantum dot geometry for maximal magnetoconductance switching ratios in an array, highlighting the role of phase changes and disorder effects.

Findings

Maximal switching ratio achieved at low magnetic fields.

Connecting a second dot enhances the switching effect.

Disorder imposes a temperature-dependent lower bound on switching ratio.

Abstract

Employing oval shaped quantum billiards connected by quantum wires as the building blocks of a linear quantum dot array, we calculate the ballistic magnetoconductance in the linear response regime. Optimizing the geometry of the billiards, we aim at a maximal finite- over zero-field ratio of the magnetoconductance. This switching effect arises from a relative phase change of scattering states in the oval quantum dot through the applied magnetic field, which lifts a suppression of the transmission characteristic for a certain range of geometry parameters. It is shown that a sustainable switching ratio is reached for a very low field strength, which is multiplied by connecting only a second dot to the single one. The impact of disorder is addressed in the form of remote impurity scattering, which poses a temperature dependent lower bound for the switching ratio, showing that this effect should be readily observable in experiments.