Low-frequency dielectric response of the charge-density wave in (TaSe4)2I

We have found the charge-density wave (CDW) in (${\mathrm{TaSe}}_4$ ${)}_2$I to display a low-frequency dielectric relaxation characterized by a distribution of relaxation times. The mean relaxation times vary between approximately ${10}^{\mathrm{-}4}$ and ${10}^{\mathrm{-}8}$ sec in the temperature range of 90 to 180 K, and display an Arrhenius temperature dependence with the same activation energy (1436 K) as the normal resistivity. This is the only material thus far studied where such a straightforward connection between CDW relaxation and the band gap has been observed.