Giant Electroclinic Effect in Chiral Smectic A Phase of Ferroelectric Liquid Crystals

Abstract
A giant electroclinic effect was observed in smectic A (SA) phases of various ferroelectric liquid crystals with spontaneous polarizations as large as several hundred µC/m2. An induced tilt angle increased linearly with an electric field, E, and tended to saturate toward 16° . The induced tilt angle of a few degrees was observable even at a temperature 20° above the SA-SC * transition. It was confirmed using several compounds that the induced tilt angle is proportional to the spontaneous polarization in SC *. The response time is less than 1 µs and, when normalized by the induced tilt angle, linearly depends on E, i.e., τ'/θ0E.