Dephasing in quantum dot molecules via exciton-acoustic phonon coupling

TL;DR

This paper presents a theoretical model for exciton-phonon interactions in quantum dot molecules, explaining observed spectral broadening and linewidth variations through non-Markovian effects and phonon wavelength matching.

Contribution

The authors develop a non-Markovian theory of exciton-phonon coupling in quantum dot molecules that explains experimental spectral broadening.

Findings

Reproduces zero-phonon line broadening trends with interdot distance

Explains linewidth variations via non-Markovian coupling effects

Highlights the role of phonon wavelength matching in spectral features

Abstract

We develop a theory of the linear optical spectrum of excitons in quantum dot molecules, including the effect of exciton-phonon coupling beyond the Markov limit. The model reproduces the general trend of the zero-phonon line broadening as a function of interdot distance, that were recently measured. The unexpectedly broad linewidths and their large variation are explained in terms of both the non-Markov nature of the coupling and of the matching of the phonon wavelength to the interdot distance.