Recent experiments on 2H-TaSe2 contradict the long-held view of the charge density wave arising from a nested band structure. An intrinsically strong coupling view, involving a charge density wave state arising as a Bose condensation of preformed excitons emerges as an attractive, albeit scantily investigated alternative. Using local density approximation plus multiorbital dynamic mean-field theory, we show that this scenario agrees with a variety of normal state data for 2H-TaSe2. Based thereupon, the ordered states in a subset of dichalcogenides should be viewed as instabilities of a correlated, preformed excitonic liquid.
@article{arxiv.1008.0942,
title = {Preformed excitonic liquid route to a charge density wave in 2H-TaSe$_2$},
author = {A. Taraphder and S. Koley and N. S. Vidhyadhiraja and M. S. Laad},
journal= {arXiv preprint arXiv:1008.0942},
year = {2015}
}