Characterization of the Torsional Piezoelectric-like Response of Tantalum Trisulfide Associated with Charge-Density-Wave Depinning

TL;DR

This study investigates the frequency and voltage dependence of torsional strains in orthorhombic TaS3, revealing polarization-related effects of charge-density waves and their sluggish dynamics, with implications for understanding CDW behavior.

Contribution

It provides the first detailed analysis of voltage-induced torsional strains in TaS3, linking strain onset to CDW polarization rather than current, and explores their dynamic response.

Findings

Strain onset occurs below CDW threshold voltages.

Strain dynamics are sluggish and sample-dependent.

No strain-induced voltage observed at low biases.

Abstract

We have studied the frequency and voltage dependence of voltage-induced torsional strains in orthorhombic TaS3 [V. Ya. Pokrovskii, et al, Phys. Rev. Lett. 98, 206404 (2007)] 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 appear 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 strain-dependent CDW conductance.