Regensburg 2007 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 31: Quantum dots and wires: Optical properties III
HL 31.1: Vortrag
Mittwoch, 28. März 2007, 14:45–15:00, H17
Measurement and control of spin and charge interactions in a single quantum dot molecule — •Emily Clark1, Hubert Krenner1, Christoph Scheurer2, Toshihira Nakaoka3, Max Bichler1, Gerhard Abstreiter1, and Jonathan Finley1 — 1Walter Schottky Institut, Technical University of Munich, Am Coulombwall 3, 85748 Garching, Germany — 2Lehrstuhl für Theoretische Chemie, Technische Universität München, Lichtenbergstraße 4, 85748 Garching, Germany — 3University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo, 153-8505, Japan
We report experiments in which we electrically manipulate coupled exciton states (neutral and negatively charged single excitons) in individual QD-molecules (QDMs). The samples investigated consist of a single pair of vertically stacked, self assembled In0.5Ga0.5As QDMs embedded into the intrinsic region of an n-type GaAs Schottky photodiode. By tuning the electric field oriented along the axis of the QDM, via the gate voltage, electrons can be predictably injected into the QDM from the back contact. Field dependant micro-Photoluminescence measurements reveal a complex series of anti-crossing features from neutral excitons, negatively charged excitons and double charged excitons as the field is lowered. Each multi-particle configuration couples at a distinct field and unique energetic splitting, allowing for the unambiguous assignment of each spectral feature. We directly probe Coulomb and Pauli blockade effects and inter-dot tunnel coupling using fully optical techniques. See: H.J. Krenner, et. al Phys. Rev. Lett. 97, 076403 (2006)