title: Coulomb Mediated Hybridization of Excitons in Coupled Quantum Dots.
abstract: 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.
authors.affiliation: Walter Schottky Institut and Physik-Department, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany.|Nanosystems Initiative Munich (NIM), Schellingstrasse 4, 80339 München, Germany.
authors.forename: P-L
authors.initials: PL
authors.lastname: Ardelt
authors.affiliation: Department of Theoretical Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Technology, 50-370 Wrocław, Poland.
authors.forename: K
authors.initials: K
authors.lastname: Gawarecki
authors.affiliation: Walter Schottky Institut and Physik-Department, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany.|E. L. Ginzton Laboratory, Stanford University, Stanford, California 94305, USA.
authors.forename: K
authors.initials: K
authors.lastname: Müller
authors.affiliation: Walter Schottky Institut and Physik-Department, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany.
authors.forename: A M
authors.initials: AM
authors.lastname: Waeber
authors.affiliation: Walter Schottky Institut and Physik-Department, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Bechtold
authors.affiliation: Walter Schottky Institut and Physik-Department, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Oberhofer
authors.affiliation: Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Strasse 10, 48149 Münster, Germany.
authors.forename: J M
authors.initials: JM
authors.lastname: Daniels
authors.affiliation: Walter Schottky Institut and Physik-Department, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Klotz
authors.affiliation: Walter Schottky Institut and Physik-Department, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Bichler
authors.affiliation: Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Strasse 10, 48149 Münster, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Kuhn
authors.affiliation: Nanosystems Initiative Munich (NIM), Schellingstrasse 4, 80339 München, Germany.|Lehrstuhl für Experimentalphysik 1 and Augsburg Centre for Innovative Technologies (ACIT), Universität Augsburg, Universitätsstrasse 1, 86159 Augsburg, Germany.
authors.forename: H J
authors.initials: HJ
authors.lastname: Krenner
authors.affiliation: Department of Theoretical Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Technology, 50-370 Wrocław, Poland.
authors.forename: P
authors.initials: P
authors.lastname: Machnikowski
authors.affiliation: Walter Schottky Institut and Physik-Department, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany.|Nanosystems Initiative Munich (NIM), Schellingstrasse 4, 80339 München, Germany.
authors.forename: J J
authors.initials: JJ
authors.lastname: Finley