Nonlinear behavior of the field-induced molecular tilt near the smectic A–C* transition

Abstract

A deviation from the linear relationship between induced molecular tilt and applied electric field has been observed in the vicinity of the transition from the smectic A to the chiral smectic C* phase. Near the transition temperature T_c, the induced tilt angle θ initially grows linearly with the strength of an applied electric field E, and clearly exhibits a crossover to E^α (1/3 <α<1) above a certain field strength. As temperature increases, however, the exponent α approaches 1 in a wide range of the electric field we studied. A simple mean field model is presented to explain the observed nonlinear behavior.