An interferometer-based setup for measurements of length of needle-like samples is developed, and
thermal expansion of o-TaS3 crystals is studied. Below the Peierls transition the temperature hysteresis of length L is
observed, the width of the hysteresis loop $\delta L/L$ being up to $5\times 10^{-5}$. Curiously, $L(T)$ changes so that
it is in front of its
equilibrium value. The hysteresis loop couples with that of conductivity. With lowering T the charge-density waves'
(CDW) elastic modulus grows and at 100 K becomes comparable with that of the lattice Yl. The results justify the
assumption about the strain dependence of the CDW wave vector and clarify the nature of the anomalies of Yl which
occur on the CDW depinning. In particular, Yl, is expected to show a strong drop in the static regime, if measured at
sufficiently small sample elongation $(\delta L/L < 10^{ -5}) $.
Modeling the spin-Peierls transition of spin-
12
chains with correlated states:
J1−J2
model,
CuGeO3
, and
TTF–CuS4C4(CF3)4
