Coulomb Mediated Hybridization of Excitons in Coupled Quantum Dots

P-L Ardelt, K Gawarecki, K Müller, A M Waeber, A Bechtold, K Oberhofer, J M Daniels, F Klotz, M Bichler, T Kuhn, H J Krenner, P Machnikowski, J J Finley

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We report Coulomb mediated hybridization of excitonic states in optically active InGaAs quantum dot molecules. By probing the optical response of an individual quantum dot molecule as a function of the static electric field applied along the molecular axis, we observe unexpected avoided level crossings that do not arise from the dominant single-particle tunnel coupling. We identify a new few-particle coupling mechanism stemming from Coulomb interactions between different neutral exciton states. Such Coulomb resonances hybridize the exciton wave function over four different electron and hole single-particle orbitals. Comparisons of experimental observations with microscopic eight-band k·p calculations taking into account a realistic quantum dot geometry show good agreement and reveal that the Coulomb resonances arise from broken symmetry in the artificial semiconductor molecule.

Original languageEnglish
Pages (from-to)077401
JournalPhysical Review Letters
Issue number7
Publication statusPublished - 19 Feb 2016

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