Properties of strained TaS₃ samples in the state of charge density wave and in the normal state

The uniaxial strain of quasi-one-dimensional conductor whiskers of orthorhombic TaS₃ at a strain higher than ε_c ~ 0.8% leads to a sharp increase in the coherence of the properties of a charge density wave (CDW), which manifests itself in its motion in fields higher than threshold field E_t. During uniaxial elongation, TaS₃ is shown to exhibit the following unusual properties even in weak fields: Peierls transition temperature T_P depends nonmonotonically on ε, one-dimensional fluctuations weaken near T_P, and the coherence length of a charge density increases at T < T_P. Investigations in fields higher than E_t show that the ultracoherent properties of CDW exist in a wide temperature range and are retained when temperature increases up to T_P. These properties of CDW make it possible to observe a sharp increase in E_t near T_P and an almost jumplike increase in E_t at T < 90 K. The increase in E_t at T_P is explained by a decrease in the coherence volume of CDW because of a fluctuational suppression of the Peierls gap.