A model of coherent creep and switching in charge density wave conduction in NbSe_3 at low temperatures

摘要

A model is proposed of the temporally ordered collective creep with finite threshold field, and of the "switching" transition to a highly conducting state at a higher threshold, observed in charge-density wave conduction in niobium triselenide by Lemay et al. [Phys. Ev. Lett. 83, 2793 (1999)]. the model is based on their suggestion that the creep involves the thermally activated advance of wavelengths of CDW past individual impurities. In the model this is achieved by the formation near the impurity of a dislocation loop, which collapses after encircling it. Switching is attributed to a transition, induced by stress associated with the motion, to a situation in which collapse is avoided. enabling the CDW to advance indefinitely. The model accounts quantitatively for the observed creep, and exhibits switching and hysteresis qualitatively similar to that observed.