Towards Bose-Einstein Condensation of Semiconductor Excitons: The Biexciton Polarization Effect
D. Hägele, S. Pfalz, M. Oestreich
We theoretically predict a strong influence of stimulated exciton-exciton scattering on semiconductor luminescence. The stimulated scattering causes circularly polarized instead of unpolarized emission at the biexciton emission line in a degenerate gas of partly spin polarized excitons. The biexciton polarization effect increases with increasing exciton densities and decreasing temperatures and approaches almost unity in the ultimate case of Bose-Einstein condensation. Time- and polarization-resolved luminescence measurements evidence the biexciton polarization effect both in ZnSe and GaAs quantum wells.
Physical Review Letters•Sep 30, 2009•4 citations