Coherence length of cold exciton gases in coupled quantum wells

A Mach-Zehnder interferometer with spatial and spectral resolution was used to probe spontaneous coherence in cold exciton gases, which are implemented experimentally in the ring of indirect excitons in coupled quantum wells. A strong enhancement of the exciton coherence length is observed at temper...

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Published inPhysical review letters Vol. 97; no. 18; p. 187402
Main Authors Yang, Sen, Hammack, A T, Fogler, M M, Butov, L V, Gossard, A C
Format Journal Article
LanguageEnglish
Published United States 03.11.2006
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Summary:A Mach-Zehnder interferometer with spatial and spectral resolution was used to probe spontaneous coherence in cold exciton gases, which are implemented experimentally in the ring of indirect excitons in coupled quantum wells. A strong enhancement of the exciton coherence length is observed at temperatures below a few Kelvin. The increase of the coherence length is correlated with the macroscopic spatial ordering of excitons. The coherence length at the lowest temperature corresponds to a very narrow spread of the exciton momentum distribution, much smaller than that for a classical exciton gas.
ISSN:0031-9007
DOI:10.1103/PhysRevLett.97.187402