Anomalous dependence of response time on the electric field in an electroclinic liquid crystal with large induced tilt and polarization

Abstract

We investigate the response time of an electroclinic liquid crystal with large induced tilt and polarization (de Vries smectic A*). The response time is found to increase with the increase in electric field up to a threshold value in contrast with the general case of a decrease with field. This behavior is unusual and contrasts with that observed for a conventional smectic-A* phase. The anomalous behavior is explained by the Langevin process of the director reorientation by assuming an increase in the effective dipole moment (?eff) with field. The response time decreases with the increase in temperature in the smectic-A* phase. We find the existence of a finite correlation length of a few tens of nm which in both temperature and field dependent.