Impurity effect on low-temperature polarisation of the charge-density-waves in o-TaS$_3$

TL;DR

This study investigates how impurity doping affects the low-temperature dielectric response of charge-density-waves in o-TaS3, revealing anomalous doping dependence and consistent activation energy across samples.

Contribution

It provides new insights into impurity effects on dielectric properties of charge-density-waves, challenging existing explanations for low-temperature dielectric anomalies.

Findings

Doped crystals exhibit higher low-temperature dielectric constants.

Characteristic time follows an activation law with ~400 K energy.

Doping causes anomalous changes in dielectric response.

Abstract

The temperature dependence of the low-temperature dielectric response is studied in o-TaS$_3$ samples doped by Nb, Se, and Ni and for nominally pure ones. It is found, that the low-temperature dielectric constant depends anomalously on doping and is higher for doped crystals, whereas the temperature dependence of the characteristic time of all samples follows the activation law with nearly the same activation energy $\sim 400$ K (T>20 K). The observed behaviour is inconsistent with all available explanations of the low-temperature dielectric anomaly.