The Aharonov-Bohm effect for an exciton

TL;DR

This paper theoretically investigates the Aharonov-Bohm effect on excitons in a ring with magnetic flux, revealing oscillations in absorption spectra despite exciton neutrality, due to quantum tunneling effects.

Contribution

It provides an exact solution for short-range electron-hole attraction and demonstrates flux-dependent oscillations in exciton absorption properties.

Findings

Spectral position of exciton peak oscillates with magnetic flux.

Oscillator strength of exciton absorption oscillates with magnetic flux.

Oscillations have a period equal to the magnetic flux quantum.

Abstract

We study theoretically the exciton absorption on a ring shreded by a magnetic flux. For the case when the attraction between electron and hole is short-ranged we get an exact solution of the problem. We demonstrate that, despite the electrical neutrality of the exciton, both the spectral position of the exciton peak in the absorption, and the corresponding oscillator strength oscillate with magnetic flux with a period $\Phi_0$---the universal flux quantum. The origin of the effect is the finite probability for electron and hole, created by a photon at the same point, to tunnel in the opposite directions and meet each other on the opposite side of the ring.