Characterization of the torsional piezoelectriclike response of tantalum trisulfide associated with charge-density-wave depinning

We have studied the frequency and voltage dependences of voltage-induced torsional strains in orthorhombic TaS3 by measuring the modulation of the resonant frequency of an rf cavity containing the sample. The strain has an onset voltage below the charge-density-wave (CDW) threshold voltages associated with changes in shear compliance and resistance, suggesting that the strain is associated with polarization of the CDW rather than CDW current. Measurements with square-wave voltages show that the strain is very sluggish, not even reaching its dc value at a frequency of 0.1 Hz, but the dynamics appears to be very sample dependent. By applying oscillating torque while biasing the sample with a dc current, we have also looked for strain-induced voltage in the sample; none is observed at the low biases where the voltage-induced strains first occur, but an induced voltage is observed at higher biases, probably associated with a strain-dependent CDW conductance.