Electric-Field Dependent Conduction by Sliding Charge-Density Waves in Transition-Metal Trichalcogenides

Abstract

Detailed measurements of electric-field-dependent conductivity by the sliding charge-density wave (CDW) were performed in NbSe₃ with various impurity concentration and also in two polytypes of TaS₃. Results were analyzed in terms of various models proposed so far. As a result, they were found to be well understood by the so-called Fukuyama-Lee-Rice model based on the semiclassical treatment of the phase of the CDW. If the depinning is interpreted as a dynamical critical phenomenon, the critical exponent was found to be 2. The analysis of temperature dependence of the threshold field clearly shows that the thermal fluctuation affects the temperature dependence of the threshold field in case of weak pinning, and that the thermally assisted hopping is the dominant origin of the temperature dependence of the threshold electric field in case of the strong pinning.