ANALYSIS OF YOUNG MODULUS ANOMALY AT THE PEIERLS TRANSITION IN TAS3

The temperature dependence of Young's modulus in o-TaS3 in the vicinit y of the charge-density-wave phase transition is analyzed. It is assum ed that strain enters the free energy through a strain-dependent trans ition temperature T(P). Successful fitting to data requires the inclus ion of a quadratic term in the strain dependence, in addition to the u sual linear one. This is equivalent to introducing a term in the modul us proportional to the charge-density-wave gap. The ratio between line ar and quadratic terms is consistent with a previous measurement of th e stress dependence of T(P).