Regensburg 2013 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 4: III-V semiconductors: mainly wells and surfaces

HL 4.3: Vortrag

Montag, 11. März 2013, 10:00–10:15, H15

Coherence measurements of dipolar, indirect excitons — J. Repp^1,2, •S. Dietl¹, G.J. Schinner², E. Schubert², A.K. Rai³, D. Reuter³, A.D. Wieck³, A.O. Govorov⁴, A. Högele², J.P. Kotthaus², and A.W. Holleitner¹ — ¹Walter Schottky Institut and Physik Department, Technische Universität München — ²Fakultät für Physik and Center for Nanoscience, Ludwig-Maximilians-Universität München — ³Angewandte Festkörperphysik, Ruhr-Universität Bochum — ⁴Department for Physics and Astronomy, Ohio University, Athens, Ohio 45701, USA

We report on electrostatically widely tunable trapping devices for dipolar indirect excitons in InGaAs-based double quantum wells. Resonantly excited direct excitons transform into such indirect excitons which are then collected in electrostatically shaped energy landscapes. With their electron and hole confined to two different quantum wells, these indirect excitons exhibit a large dipole moment and long lifetimes. Employing a 3He-cooled confocal microscope at temperatures below 250 mK, we generate indirect excitons at a location outside the traps and measure their photoluminescence from the trap center after they have been cooled to lattice temperatures. Since the thermal de Broglie wavelength exceeds the excitonic separation in this temperature regime, many-body correlations between trapped indirect excitons are expected. We report on measurements of the temporal and spatial coherence of the emitted photoluminescence and discuss the coherence of the exciton ensemble.