Quantenkondensation in Elektron-Loch-Photon-Systemen

Diese Schrift umfaßt eine Reihe von Arbeiten zur Quantenkondensation in Elektron-Loch-Plasmen bzw. Exzitonengasen in Halbleitern, insbesondere der Bose-Einstein-Kondensation der Exzitonen. Neben einem generellen Zugang zur Quantenkondensation in Elektron-Loch-Systemen und deren Ionisationsgleichgewicht werden Thermodynamik und Kinetik des Exzitonengases in einer Potentialfalle untersucht. Zudem wird ein theoretischer Zugang zur exzitonischen Lumineszenz erarbeitet. Der Fokus liegt stets auf den Bedingungen für das Auftreten des Kondensats und dessen experimentell beobachtbaren Signaturen

Condensation of Excitons in Cu2O at Ultracold Temperatures: Experiment and Theory

We present experiments on the luminescence of excitons confined in a potential trap at milli-Kelvin bath temperatures under cw-excitation. They reveal several distinct features like a kink in the dependence of the total integrated luminescence intensity on excitation laser power and a bimodal distribution of the spatially resolved luminescence. Furthermore, we discuss the present state of the theoretical description of Bose-Einstein condensation of excitons with respect to signatures of a condensate in the luminescence. The comparison of the experimental data with theoretical results with respect to the spatially resolved as well as the integrated luminescence intensity shows the necessity of taking into account a Bose-Einstein condensed excitonic phase in order to understand the behaviour of the trapped excitons.Comment: 41 pages, 23 figure

Scattering of Rydberg excitons by phonon-plasmon modes

AbstractWe propose a new scattering mechanism of Rydberg excitons, i.e., those with high principal quantum numbers, namely scattering by coupled LO phonon-plasmon modes, which becomes possible due to small differences in energies of the states due to different quantum defects. Already in very low-density electron–hole plasmas these provide a substantial contribution to the excitonic linewidth. This effect should allow determining plasma densities by a simple line shape analysis. Whenever one expects that low-density electron–hole plasma is present the plasmon induced broadening is of high significance and must be taken into account in the interpretation