Nonclassical effects that signal condensation of indirect excitons in CQW

AlAsGaAs-small
  • Strong enhancement of the exciton radiative decay rate consistent with exciton condensate superradiance (macroscopic dipole)
  • Strong enhancement of the exciton mobility consistent with the onset of exciton superfluidity
  • Huge fluctuations of the exciton emission consistent with critical fluctuations near the phase transition

L.V. Butov, A. Zrenner, G. Bohm, G. Weimann, Condensation of indirect excitons in coupled AlAs/GaAs quantum wells, J. de Physique 3, 167 (1993).

L.V. Butov, A. Zrenner, G. Abstreiter, G. Bohm, G. Weimann, Condensation of indirect excitons in coupled AlAs/GaAs quantum wells, Phys. Rev. Lett. 73, 304 (1994).

L.V. Butov and A.I. Filin, Anomalous transport and luminescence of indirect excitons in AlAs/GaAs coupled quantum wells as evidence for exciton condensation, Phys. Rev. B 58, 1980 (1998).

stim-scat-small

stim-scat-et-small

  • Strong enhancement of the exciton scattering rate with increasing exciton concentration consistent with bosonic stimulation of exciton scattering, which is a key signature of a degenerate Bose-gas of excitons

L.V. Butov, A.L. Ivanov, A. Imamoglu, P.B. Littlewood, A.A. Shashkin, V.T. Dolgopolov, K.L. Campman, and A.C. Gossard, Stimulated scattering of indirect excitons in coupled quantum wells: Signature of a degenerate Bose-gas of excitons, Phys. Rev. Lett. 86, 5608 (2001).