Exciton polarization, fine structure splitting and quantum dot asymmetry under uniaxial stress

TL;DR

This paper establishes a theoretical relation between fine structure splitting and exciton polarization in quantum dots under uniaxial stress, validated by atomistic calculations, aiding in the selection of optimal quantum dots for entangled photon sources.

Contribution

The paper derives a general relation linking FSS and exciton polarization angle under stress, providing a predictive tool for quantum dot optical properties.

Findings

FSS lower bound can be predicted from polarization angle and zero-stress FSS.

Critical stress is determined by changes in exciton polarization angle.

Atomistic calculations confirm the theoretical predictions.

Abstract

We derive a general relation between the fine structure splitting (FSS) and the exciton polarization angle of self-assembled quantum dots (QDs) under uniaxial stress. We show that the FSS lower bound under external stress can be predicted by the exciton polarization angle and FSS under zero stress. The critical stress can also be determined by monitoring the change in exciton polarization angle. We confirm the theory by performing atomistic pseudopotential calculations for the InAs/GaAs QDs. The work provides a deep insight into the dots asymmetry and their optical properties, and a useful guide in selecting QDs with smallest FSS which are crucial in entangled photon sources applications.