Publication Date:
2017-02-28
Description:
Author(s): Sebastian Dietl, Sheng Wang, Dieter Schuh, Werner Wegscheider, Jörg P. Kotthaus, Aron Pinczuk, Alexander W. Holleitner, and Ursula Wurstbauer There have long been considerable efforts to study the many-body quantum phase diagram and quantum phase transitions of interacting bosonic particles in solid-state systems. The particular aim is the realization and identification of Bose-Einstein condensation, a coherent ground state with all particles condensed into a macroscopic many-body ground-state wave function. The authors probe photogenerated excitonic ensembles in coexistence with a two-dimensional hole system confined in GaAs double quantum well structures and electrostatically trapped by local gate electrodes using photoluminescence and resonant inelastic light scattering experiments. In this work, the authors observe a collective excitation mode at the transferred in-plane momentum and an energy of only 0.44 meV. This mode is interpreted as a plasma excitation of the two-dimensional excess hole subsystem coupled to the excitonic system. In this respect, the two subsystems behave like coupled oscillators. The plasmon energy is determined by the many-body interaction between the photogenerated exciton and hole subsystems. The low-energy excitation spectrum particularly of the excitonic system can play a key role in identifying Bose-Einstein condensation of excitonic ensembles, where, for example, roton excitations are expected. [Phys. Rev. B 95, 085312] Published Mon Feb 27, 2017
Keywords:
Semiconductors II: surfaces, interfaces, microstructures, and related topics
Print ISSN:
1098-0121
Electronic ISSN:
1095-3795
Topics:
Physics
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