Stimulated Scattering of Indirect Excitons in Coupled Quantum Wells: 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; A. C. Gossard

doi:10.1103/PhysRevLett.86.5608

Stimulated Scattering of Indirect Excitons in Coupled Quantum Wells: 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

Phys. Rev. Lett. 86, 5608 – Published 11 June 2001

Abstract

We observe and analyze strongly nonlinear photoluminescence kinetics of indirect excitons in GaAs/AlGaAs coupled quantum wells at low bath temperatures, $\geq 50 mK$ . The long recombination lifetime of indirect excitons promotes accumulation of these Bose particles in the lowest energy states and allows the photoexcited excitons to cool down to temperatures where the dilute 2D gas of indirect excitons becomes statistically degenerate. Our main result—a strong enhancement of the exciton scattering rate to the low-energy states with increasing concentration of the indirect excitons—reveals bosonic stimulation of exciton scattering, which is a signature of a degenerate Bose-gas of excitons.

Received 19 January 2001

DOI:https://doi.org/10.1103/PhysRevLett.86.5608

Authors & Affiliations

L. V. Butov^1,*, A. L. Ivanov², A. Imamoglu³, P. B. Littlewood^4,5, A. A. Shashkin¹, V. T. Dolgopolov¹, K. L. Campman³, and A. C. Gossard³

¹Institute of Solid State Physics, Russian Academy of Sciences, 142432 Chernogolovka, Russia
²Department of Physics and Astronomy, Cardiff University, Cardiff CF24 3YB, Wales, United Kingdom
³Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106
⁴Department of Physics, TCM, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
⁵Bell Laboratories, Lucent Technologies, Murray Hill, New Jersey 07974