Metallic properties of 1:1 Charge-transfer salt DMTSA-BF4

Although DMTSA-BF4 has a half-filled band, the electrical resistivity and thermopower shows that this compound is metallic and undergoes metal-insulator transition at ca. 150 K. By polarized reflection spectrum, this compound is characterized as a pseudo-one-dimensional metal with a bandwidth of 0.8 eV. The band calculation suggests a one-dimensional nature of the Fermi surface. The optical transition from the bottom of the conduction band to the top of the folded conduction band is observed in the infrared region. The temperature dependence of the reflection spectrum suggests a strong fluctuation of the lattice dimerization above the phase transition temperature.