Abstract
Dipolar excitons are long-lived quasi-particle excitations in semiconductor heterostructure that carry an electric dipole. Cold dipolar excitons are expected to have new quantum and classical multi-particle correlation regimes, as well as several collective phases, resulting from the intricate interplay between the many-body interactions and their quantum nature. Here we show experimental evidence of a few correlation regimes of a cold dipolar exciton fluid, created optically in a semiconductor bilayer heterostructure. In the higher temperature regime, the average interaction energy between the particles shows a surprising temperature dependence, which is evidence for correlations beyond the mean field model. At a lower temperature, there is a sharp increase in the interaction energy of optically active excitons, accompanied by a strong reduction in their apparent population. This is evidence for a sharp macroscopic transition to a dark state, as has been suggested theoretically.
| Original language | English |
|---|---|
| Article number | 2335 |
| Journal | Nature Communications |
| Volume | 4 |
| DOIs | |
| State | Published - 2013 |
Bibliographical note
Funding Information:We would like to thank Oded Agam, Paulo Santos and Snezana Lazic for useful discussions. Y.S., K.C. and R.R. acknowledge funding from the D.F.G. Project no. 581021 and by the Israeli Science Foundation Project no. 1319/12. The work at Princeton was partially funded by the Gordon and Betty Moore Foundation through Grant no. GBMF2719 and by the National Science Foundation MRSEC-DMR-0819860 at the Princeton Center for Complex Materials.