Conquer the fine structure splitting of excitons in self-assembled InAs/GaAs quantum dots via combined stresses

TL;DR

This paper demonstrates that the fine structure splitting of excitons in self-assembled InGaAs/GaAs quantum dots can be fully suppressed using combined stresses, enabling high-quality entangled photon pair generation.

Contribution

The study introduces a method to eliminate FSS in quantum dots through combined stresses, confirmed by atomic pseudopotential calculations, advancing quantum photonics.

Findings

FSS can be tuned to less than 0.1 μeV in studied QDs.

Combined stresses along [110] and [010] directions effectively suppress FSS.

The method enables high-quality entangled photon emission.

Abstract

Eliminating the fine structure splitting (FSS) of excitons in self-assembled quantum dots (QDs) is essential to the generation of high quality entangled photon pairs. It has been shown that the FSS has a lower bound under uniaxial stress. In this letter, we show that the FSS of excitons in a general self-assembled InGaAs/GaAs QD can be fully suppressed via combined stresses along the [110] and [010] directions. The result is confirmed by atomic empirical pseudopotential calculations. For all the QDs we studied, the FSS can be tuned to be vanishingly small ($<$ 0.1 $\mu$eV), which is sufficient small for high quality entangled photon emission.