Metal-Insulator Transition in the Organic Metal(TTM−TTP)I3with a One-Dimensional Half-Filled Band

The title 1:1 composition organic conductor, with a highly one-dimensional half-filled energy band, exhibits metallic conductivity down to $T_{\mathrm{MI}}\approx 160\mathrm{K}$, but the spin susceptibility follows the one-dimensional Heisenberg model from room temperature to 2 K, without any anomaly at $T_{\mathrm{MI}}$. The insulating state is regarded as a Mott insulator. The small $U$, related to the extended molecular structure, gives rise to the small charge gap and the high-temperature metallic conduction.