We have investigated the low-frequency complex conductivity of the charge-density-wave condensate in ${\mathrm{Tl}}_{0.3}$${\mathrm{MoO}}_3$, in the temperature range 40–90 K, by the measurement of admittance sampled in the frequency interval 5 Hz–13 MHz. The observed response can be characterized in terms of a simple Debye relaxation model with a distribution of relaxation times by analogy with the reported behavior of its isostructural analog ${\mathrm{K}}_{0.3}$${\mathrm{MoO}}_3$. Despite qualitative similarities with the general trends observed in ${\mathrm{K}}_{0.3}$${\mathrm{MoO}}_3$, the relaxational response in ${\mathrm{Tl}}_{0.3}$${\mathrm{MoO}}_3$ differed significantly in detail. Both the mean relaxation times (${\tau }_0$) and static dielectric constants (${\epsilon }_0$) are shown to have Arrhenius temperature dependence with activation energies of 743 and 152 K, respectively. For applied dc biases above the threshold field ($E_T$) for nonlinear conduction, the response shows structure at frequencies that resemble ‘‘washboard’’ characteristics of a moving charge condensate. From the values of the high-frequency real and imaginary parts of the dielectric constants, the existence of yet another relaxation process is proposed.

• Received 19 February 1988

DOI:https://doi.org/10.1103/PhysRevB.38.7243