Far-Infrared Study of the Charge Density Wave in Tetrathiafulvalene Tetracyanoquinodimethane (TTF-TCNQ)

Detailed far-infrared measurements at temperatures from 25 to 300 K provide strong support for a charge-density-wave mechanism for the dc conductivity and microwave dielectric constant of tetrathiafulvalene tetracyanoquinodimethane (TTF-TCNQ). At low temperatures the charge-density wave is pinned at 40 ${\mathrm{cm}}^{-1\mathrm{}}$ while at higher temperatures it appears at zero frequency. Values are obtained for the effective mass ($20m^{*}$) and lifetime (1.6×${10}^{-12\mathrm{}}$ sec at 60 K) of the charge-density wave.