Impurity effect on low-temperature polarisation of the charge-density-waves in o-TaS3

The temperature dependence of the low-temperature dielectric response is st udied in o-TaS3 samples doped by Nh, Se, and Ni and for nominally pure ones . It is found that the low-temperature dielectric constant depends anomalou sly on doping and is higher for doped crystals. whereas the temperature dep endence of the characteristic time of all samples follows the activation la w with nearly the same activation energy similar to 400 K (T > 20 K). The o bserved behaviour is inconsistent with all available explanations of the lo w-temperature dielectric anomaly. (C) 1999 Published by Elsevier Science B. V.