Electric Control of the Exciton Fine Structure in Non-Parabolic Quantum Dots

TL;DR

This paper demonstrates how non-parabolic confinement potentials influence exciton fine-structure splitting in quantum dots and shows electric fields can be used to eliminate FSS, enabling entangled photon generation.

Contribution

It reveals the role of non-parabolic potentials in FSS behavior and proposes electric field control for entangled photon production in quantum dots.

Findings

Non-parabolic confinement causes non-monotonic FSS behavior.

Hard-wall potential aligns better with experimental FSS data.

Electric fields can eliminate FSS to produce entangled photons.

Abstract

We show that the non-parabolic confinement potential is responsible for the non-monotonic behavior and sign change of the exciton fine-structure splitting (FSS) in optically active self-assembled quantum dots. This insight is important for the theoretical understanding and practical control by electric fields of the quantum state of the emitted light from a biexciton cascade recombination process. We find that a hard-wall (box) confinement potential leads to a FSS that is in better agreement with experimentally measured FSS than a harmonic potential. We then show that a finite applied electric field can be used to remove the FSS entirely, thus allowing for the creation of maximally entangled photons, being vital to the growing field of quantum communication and quantum key distribution.