STATIC AND LOW-FREQUENCY SHEAR COMPLIANCE OF TAS3

We have measured torsional strains in the charge-density-wave (CDW) conductor TaS3 as functions of stress (i.e., torque), stress frequency (2 mHz to 20 Hz), and sample voltage. At all frequencies, the compliance is observed to increase by approximate to 25% when the voltage is increased above the threshold for CDW depinning, implying that the time constant for CDW relaxation in the pinned state is >84 s. Above 30 mHz, the depinned compliance has a slow frequency dependence, implying a large distribution of relaxation times extending to at least 5 s. We also observe a current-reversible strain-memory effect, which may account for the failure of previous investigators to observe static elastic softening when the CDW is depinned.