Stiffness reduction associated with charge-density-wave sliding: Temperature and bias dependences inTaS3

Young’s modulus was measured as a function of electrical bias on o-${\mathrm{TaS}}_3$ between 60 K and the Peierls transition temperature, ${\mathit{T}}_{\mathit{c}}$=220 K. ${\mathit{Y}}_{\mathrm{CDW}}$, the modulus difference between stationary and rapidly sliding charge-density-wave states, increases as the square of the order parameter immediately below ${\mathit{T}}_{\mathit{c}}$. A second rise begins below 160 K. The shape of the reduction of modulus with bias is controlled predominantly by the excess current, ${\mathit{I}}_{\mathrm{CDW}}$, and is fit with a stretched exponential. These results are interpreted according to the recently presented phase-relaxation model.