This article is cited in 3 papers

International school-seminar ''Excitons in crystals and semiconductor nanostructures'', dedicated to the 120th anniversary of the birth of E. F. Gross, St. Petersburg, October 10-12, 2017
Optical Properties

Emission of Cu$_{2}$O paraexcitons confined by a strain trap: hints of a Bose–Einstein condensate?

D. Fröhlich^a, M. Bayer<sup>ab

a</sup> Experimentelle Physik II, Universität Dortmund
^b Ioffe Institute, Russian Academy of Sciences, St. Petersburg, Russia

Abstract: We monitor the phonon sideband emission from paraexcitons confined in a strain trap in cuprous oxide at $T$ = 1.25 K. On the low energy ank of the optical phonon replicas, both of $\Gamma_{5}^{-}$ and $\Gamma_{3}^{-}$ symmetry (the latter activated by application of a magnetic field), we detect sharp peaks that might represent indications for a paraexciton Bose-Einstein condensate. In contrast, such peaks are absent in the phonon-mediated emission of the orthoexcitons, and they also disappear at elevated temperatures. The results challenge our understanding of the involved physics, e. g., of the Auger recombination of excitons, which has so far been believed to prevent crossing the border to a condensate.

Language: English

DOI: 10.21883/FTT.2018.08.46248.12Gr

 English version: Physics of the Solid State, 2018, 60:8, 1600–1605

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