We present a new high-resolution angle-resolved photoemission study of 1\textit{T}-TiSe2 in both, its room-temperature, normal phase and its low-temperature, charge-density wave phase. At low temperature the photoemission spectra are strongly modified, with large band renormalisations at high-symmetry points of the Brillouin zone and a very large transfer of spectral weight to backfolded bands. A theoretical calculation of the spectral function for an excitonic insulator phase reproduces the experimental features with very good agreement. This gives strong evidence in favour of the excitonic insulator scenario as a driving force for the charge-density wave transition in 1\textit{T}-TiSe2.
@article{arxiv.0704.0159,
title = {Evidence for an excitonic insulator phase in 1T-TiSe$_{2}$},
author = {H. Cercellier and C. Monney and F. Clerc and C. Battaglia and L. Despont and M. G. Garnier and H. Beck and L. Patthey and H. Berger and P. Aebi},
journal= {arXiv preprint arXiv:0704.0159},
year = {2009}
}