Characterization of the half-filled DMTSA-BF4 by optical and magnetic measurements

Quasi one-dimensional half-filled radical salt DMTSA-BF4 shows high conductivity (σgp ≈ 450Ω−1cm−1 ) and the metal-like temperature dependence down to ca. 180K, in contrast to the conventional half-filled organic charge-transfer salts. By the physical properties measurements we characterize the compound as a metal around room temperature due to the large t. On lowering temperature the system undergoes Peierls transition and becomes a semiconductor. Hubbard parameters Ueff and t for DMTSA-BF4 are estimated at 1.2 eV and 0.36 eV respectively.