Dresden 2006 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 50: Poster II
HL 50.36: Poster
Donnerstag, 30. März 2006, 16:30–19:00, P3
Strongly correlated excitons in quantum wells — •Patrick Ludwig1,2, Alexei Filinov2, Michael Bonitz2, and Heinrich Stolz1 — 1Universität Rostock, Institut für Physik, Universitätsplatz 3, 18051 Rostock, Germany — 2Christian-Albrechts-Universität zu Kiel, ITAP, Leibnitzstrasse 15, 24098 Kiel, Germany
In this work we consider small ensembles of optically excited indirect excitons in a quantum well (QW). The spatial separation of electrons and holes and lateral exciton confinement is due to the quantum confined Stark effect produced by an external electric field of a single tip electrode. The typical trap size is of the order of several micrometers.
Using first principle Path Integral Monte Carlo simulations, we first compute the lateral confinement potential of the excitons and the effective exciton-exciton interaction potential in the presence of the electric field. These results are then used in classical thermodynamic Monte Carlo simulations to investigate systems of several tens to thousands of indirect excitions in GaAs-based QWs. By changing the field strength, the excitation intensity (exciton number) and temperature, the exciton-exciton correlations can be varied in broad ranges. We present results for the density distribution, correlation functions and the phase diagram in the density- temperature-field strength space. Our theoretical results allow us to predict the parameter range at which interesting many-particle states, including exciton crystallization should be observable in experiments.