Excitonic Aharonov-Bohm effect in a two-dimensional quantum ring

TL;DR

This paper theoretically investigates the optical properties of excitons in a two-dimensional quantum ring with magnetic flux, revealing persistent Aharonov-Bohm oscillations influenced by the ring's width and topology.

Contribution

It provides an analytic solution for excitonic Aharonov-Bohm effects in 2D rings with tunable width, highlighting the robustness of oscillations due to non-simply connected confinement.

Findings

Oscillatory oscillator strength depends on magnetic flux due to Aharonov-Bohm effect.

Oscillation amplitude decreases with increasing ring width.

Oscillations remain finite even for rings with width comparable to radius.

Abstract

We study theoretically the optical properties of an exciton in a two-dimensional ring threaded by a magnetic flux. We model the quantum ring by a confining potential that can be continuously tuned from strictly one-dimensional to truly two-dimensional with finite radius-to-width ratio. We present an analytic solution of the problem when the electron-hole interaction is short-ranged. The oscillatory dependence of the oscillator strength as a function of the magnetic flux is attributed to the Aharonov-Bohm effect. The amplitude of the oscillations changes upon increasing the width of the quantum ring. We find that the Aharonov-Bohm oscillations of the ground state of the exciton decrease with increasing the width, but remarkably the amplitude remains finite down to radius-to-width ratios less than unity. We attribute this resilience of the excitonic oscillations to the non-simply connectedness of our chosen confinement potential.