Nonlinear Dielectric Spectroscopy of an Antiferroelectric Liquid Crystal MHPOBC : Soft Mode Condensation in SmA

Abstract

We have experimentally and theoretically studied the nonlinear dielectric response under large orientational fluctuations near the SmA-SmC_α^* phase transition point in a chiral smectic liquid crystal MHPOCBC. The third-order nonlinear dielectric response due to the fluctuations was observed in the vicinity of the transition point. By using it, we have successfully observed for the first time the soft mode condensation inducing the SmA-SmC_α^* phase transition.