Dielectric investigation of the sliding charge-density wave in Tl0.3MoO3

We have investigated the low-frequency complex conductivity of the charge-density-wave condensate in Tl0.3MoO3, in the temperature range 4090 K, by the measurement of admittance sampled in the frequency interval 5 Hz13 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 K0.3MoO3. Despite qualitative similarities with the general trends observed in K0.3MoO3, the relaxational response in Tl0.3MoO3 differed significantly in detail. Both the mean relaxation times (0) and static dielectric constants (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 (ET) 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.