Spectral broadening of optical transitions at tunneling resonances in InAs/GaAs coupled quantum dot pairs

Le résumé fourni par la source

We report on line-width analysis of optical transitions in InAs/GaAs coupled quantum dots as a function of bias voltage, temperature, and tunnel coupling strength. A significant line broadening up to 100 $\ensuremath{\mu}\mathrm{eV}$ is observed at hole tunneling resonances where the coherent tunnel coupling between spatially direct and indirect exciton states is maximized, corresponding to a phonon-assisted transition rate of $150\phantom{\rule{0.16em}{0ex}}{\mathrm{ns}}^{\ensuremath{-}1}$ at 20 K. With increasing temperature, the linewidth shows broadening characteristic of single-phonon transitions. The linewidth as a function of tunnel coupling strength tracks the theoretical prediction of line-width broadening due to phonon-assisted transitions, and is maximized with an energy splitting between the two exciton branches of $0.8\ensuremath{-}0.9\phantom{\rule{0.16em}{0ex}}\mathrm{meV}$. This report highlights the line-width broadening mechanisms and fundamental aspects of the interaction between these systems and the local environment.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.