Metal-insulator transition of the 1-D half-filled band metal (TTM-TTP)I3

(TTM-TTP)I3, in sprite of its 1-D half-filled band, exhibits the metallic conduction at room temperature. Resistance, susceptibility, X-ray diffuse scattering studies revealed a phase transition at Tc ≈ 110 K below which the resistivity increases rapidly, the susceptibility decreases and the 2 kF = 0.5 c* superstructure sets in. The nature of the transition is discussed in the light of the band structure and the precursor effect at higher temperatures.