Conductivity of the One-Dimensional Conductor Tetrathiafulvalene-Tetracyanoquinodimethane (TTF-TCNQ) near Commensurability

Abstract

We report an important drop in the longitudinal conductivity of TTF-TCNQ occurring at constant temperature in the metallic phase and in a narrow pressure domain located around 19 kbar. The drop of conductivity has been related to a \ifmmode\times\else\texttimes\fi{} 3 commensurability of the longitudinal distortion with the lattice. This experiment, together with x-ray diffuse scattering of TTF-TCNQ could suggest that a significant fraction of the metallic conductivity below ambient temperature is due to the fluctuating collective mode.