An exciton gas on a lattice is analyzed in terms of a convergent hopping expansion. For a given chemical potential our calculation provides a sufficient condition for the hopping rate to obtain an exponential decay of the exciton correlation function. This result indicates the existence of a Mott phase in which strong fluctuations destroy the long range correlations in the exciton gas at any temperature, either by thermal or by quantum fluctuations.
@article{arxiv.1508.03904,
title = {Short note on the excitonic Mott phase},
author = {K. Ziegler and O. L. Berman and R. Ya. Kezerashvili},
journal= {arXiv preprint arXiv:1508.03904},
year = {2016}
}