Radiative darkbright instability and the critical Casimir effect in DQW exciton condensates
| Autor: | Tuğrul Hakioğlu, Ege Özgün |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: |
Casimir force
Condensed phase D. Radiation effects Exciton Ground state Radiation effects A. Quantum well Layer separation Spin degeneracy Instability Interband Casimir effects Materials Chemistry Radiative transfer Nonperturbative Quantum well Semiconductor quantum wells Physics Condensed Matter::Quantum Gases Condensed matter physics business.industry Condensed Matter::Other Electron-electron interaction General Chemistry Semiconductor State concentration Condensed Matter Physics Condensed Matter::Mesoscopic Systems and Quantum Hall Effect Double quantum well A. Semiconductor Casimir effect Interband coupling Critical Casimir forces Quantum theory Discontinuous derivatives Excitons Atomic physics Double quantum business D. Electronelectron interaction Order parameter |
| Zdroj: | Solid State Communications |
| Popis: | It is already well known that radiative interband interaction in the excitonic normal liquid in semiconducting double quantum wells is responsible for a negligible splitting between the energies of the dark and bright excitons enabling us to consider a four fold spin degeneracy. This has also lead many workers to naively consider the same degeneracy in studying the condensate. On the other hand, the non-perturbative aspects of this interaction in the condensed phase, e.g. its consequences on the order parameter and the darkbright mixture in the ground state have not been explored. In this work, we demonstrate that the ground state concentrations of the dark and the bright exciton condensates are dramatically different beyond a sharp interband coupling threshold where the contribution of the bright component in the ground state vanishes. This shows that the effect of the radiative interband interaction on the condensate is nonperturbative. We also observe in the free energy a discontinuous derivative with respect to the layer separation at the entrance to the condensed phase, indicating a strong critical Casimir force. An estimate of its strength shows that it is measurable. Measuring the Casimir force is challenging, but at the same time it has a conclusive power about the presence of the long sought for condensed phase. © 2011 Elsevier Ltd. All rights reserved. |
| Databáze: | OpenAIRE |
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