We report experiments showing that spatially indirect excitons confined in a wide single quantum well can exhibit macroscopic spatial coherence. Extended coherence is spontaneously established in the regime where indirect excitons form a distinctive ring shaped pattern fragmented into microscopic beads. These contain a large concentration of indirect excitons at sub-Kelvin temperatures, the excitons spatial coherence being the greatest in the vicinity of the fragments.
@article{arxiv.1210.3176,
title = {Observation of macroscopic coherence in self-organized dipolar excitons},
author = {M. Alloing and D. Fuster and Y. Gonzalez and L. Gonzalez and F. Dubin},
journal= {arXiv preprint arXiv:1210.3176},
year = {2012}
}