Pseudogaps in nearly one-dimensional metals

Abstract

The linear chain conductors called the Bechgaard salts are materials where the electronic band is half filled, electron–electron interactions are moderate and the interchain transfer integral is varied from salt to salt. Spectroscopic evidences point to a transition from a (1D) insulating, Mott–Hubbard (MH) state to a conducting state when the interchain transfer integral exceeds the MH pseudogap. The conducting state is that of a correlation induced semimetal with the majority of charge excitations gapped, and with charge–spin separation. Spectroscopic evidences also point to a Tomonaga–Luttinger liquid at energies exceeding the interchain transfer integral.