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Torsional Strain of TaS$_3$ Whiskers on the Charge-Density Waves Depinning

V. Ya. Pokrovskii·S. G. Zybtsev·I. G. Gorlova
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Abstract

We find that electric current $I$ exceeding the threshold value results in torsion deformation of o-TaS$_3$ samples with one contact freely suspended. The rotation angle, $δϕ$, of the free end achieves several degrees and exhibits hysteresis as a function of $I$. The sign of $δϕ$ depends on the $I$ polarity; a polar axis along the conducting chains (the {\it c}-axis) is pointed out. We associate the effect with surface shear of the charge-density waves (CDW) coupled to the crystal shear. The current-induced torsional strain could be treated in terms of enormous piezoelectric coefficients ($>10^{-4}$ cm/V) corresponding to shear. In essence, TaS$_3$ appears to be a ready torsional actuator based on the unique intrinsic property of the CDW.

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V. Ya. Pokrovskii, S. G. Zybtsev, I. G. Gorlova. 2007-02-07. Torsional Strain of TaS$_3$ Whiskers on the Charge-Density Waves Depinning. https://doi.org/10.1103/physrevlett.98.206404

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