Strong-Pinning Effects in Low-Temperature Creep: Charge-Density Waves in TaS_3

TL;DR

This paper investigates low-temperature nonlinear conduction in o-TaS_3, revealing multiple I-V branches due to strong pinning impurities, with implications for understanding collective transport in various physical systems.

Contribution

It demonstrates the sequential freezing-out of conduction branches caused by different impurity types, linking microscopic pinning effects to macroscopic transport behavior.

Findings

Multiple I-V branches observed below a few Kelvins.

Sequential freezing-out of branches with decreasing temperature.

Impurity-specific origins of each conduction branch.

Abstract

Nonlinear conduction in the quasi-one dimensional conductor o-TaS_3 has been studied in the low-temperature region down to 30 mK. It was found that at temperatures below a few Kelvins the current-voltage (I-V) characteristics consist of several branches. The temperature evolution of the I-V curve proceeds through sequential freezing-out of the branches. The origin of each branch is attributed to a particular strong pinning impurity type. Similar behavior is expected for other physical systems with collective transport (spin-density waves, Wigner crystals, vortex lattices in type-II superconductors etc.) in the presence of strong pinning centers.