Phase Diagram of Degenerate Exciton Systems
C. W. Lai,1,3*
J. Zoch,2
A. C. Gossard,4
D. S. Chemla1,2,3
Degenerate exciton systems have been produced in quasi–two-dimensional
confined areas in semiconductor coupled quantum well structures.
We observed contractions of clouds containing tens of thousands
of excitons within areas as small as (10 µm)
2 near 10
kelvin. The spatial and energy distributions of optically active
excitons were determined by measuring photoluminescence as a
function of temperature and laser excitation and were used as
thermodynamic quantities to construct the phase diagram of the
exciton system, which demonstrates the existence of distinct
phases. Understanding the formation mechanisms of these degenerate
exciton systems can open new opportunities for the realization
of Bose-Einstein condensation in the solid state.
2 Physics Department, University of California at Berkeley, Berkeley, CA 94720, USA.
3 Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
4 Department of Electrical and Computer Engineering, University of California at Santa Barbara, Santa Barbara, CA 93106, USA.
* To whom correspondence should be addressed. E-mail: celai{at}lbl.gov
