Structural symmetry-breaking to explain radiative Auger transitions in self-assembled quantum dots

TL;DR

This paper investigates how symmetry-breaking in self-assembled quantum dots influences radiative Auger transitions, combining experimental measurements with theoretical modeling to explain additional emission lines.

Contribution

It introduces a composition fluctuation model and group theory analysis to explain radiative Auger lines, advancing understanding of symmetry effects in quantum dot emissions.

Findings

Excellent agreement between model and measurements

Symmetry-breaking causes additional emission lines

Composition fluctuations influence Auger transition strength

Abstract

The optical spectrum of a quantum dot is typically dominated by the fundamental transition between the lowest-energy configurations. However, the radiative Auger process can result in additional red-shifted emission lines. The origin of these lines is a combination of Coulomb interaction and symmetry-breaking in the quantum dot. In this paper, we present measurements of such radiative Auger lines for a range of InGaAs/GaAs self-assembled quantum dots and use a tight-binding model with a configuration interaction approach to explain their appearance. Introducing a composition fluctuation cluster in the dot, our calculations show excellent agreement with measurements. We relate our findings to group theory explaining the origin of the additional emission lines. Our model and results give insight into the interplay between the symmetry breaking in a quantum dot and the position and strength of the radiative Auger lines.