Interplay of electronic correlations and lattice instabilities in BaVS3

The quasi-one-dimensional metallic system BaVS3 with a metal-insulator transition at T-MI=70 K shows large changes in the optical phonon spectrum, a central peak, and an electronic Raman scattering continuum that evolve in a three-step process. Motivated by the observation of a strongly fluctuating precursor state at high temperatures and orbital ordering and a charge gap at low temperatures, we suggest a concerted action of the orbital, electronic, and lattice subsystems in BaVS3 dominated by electronic correlations.