We investigate the interband transitions in several ensembles of self-assembled InAs/GaAs quantum dots by using photoluminescence excitation spectroscopy under strong magnetic field. Well defined resonances are observed in the spectra. A strong anticrossing between two transitions is observed in all samples, which cannot be accounted for by a purely excitonic model. The coupling between the mixed exciton-LO phonon states is calculated using the Fr\"{o}hlich Hamiltonian. The excitonic polaron energies as well as the oscillator strengths of the interband transitions are determined. An anticrossing is predicted when two exciton-LO phonon states have close enough energies with phonon occupations which differ by one. A good agreement is found between the calculations and the experimental data evidencing the existence of excitonic polarons.
@article{arxiv.cond-mat/0609506,
title = {Evidence for excitonic polarons in InAs/GaAs quantum dots},
author = {Vanessa Preisler and Thomas Grange and Robson Ferreira and Louis-Anne De Vaulchier and Yves Guldner and Fransisco José Teran and Marek Potemski and Aristide Lemaître},
journal= {arXiv preprint arXiv:cond-mat/0609506},
year = {2016}
}