Abstract
We have investigated the low-frequency complex conductivity of the charge-density-wave condensate in , 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 . Despite qualitative similarities with the general trends observed in , the relaxational response in differed significantly in detail. Both the mean relaxation times () and static dielectric constants () are shown to have Arrhenius temperature dependence with activation energies of 743 and 152 K, respectively. For applied dc biases above the threshold field () 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
©1988 American Physical Society