Abstract
The effect of external static electric field on the dynamics of Goldstone orientational mode in ferroelectric liquid crystal was studied by photon correlation spectroscopy in the Sm C* phase of 4-(2′-methylbutyl) phenyl 4′-n-octylbiphenyl-4-carboxylate (CE8). In the field lower than the critical field necessary to unwind the helical structure of the crystal, the relaxation rate of the mode is almost field independent at all scattering wave vectors. At the critical field it suddenly increases and then continues to slowly increase with the field.
The spatial dispersion of the mode which is parabolic with minimum at helical wave vector qo in the undisturbed sample, remains unchanged below the critical field. Above the critical field the minimum in the dispersion at qo disappears.