Electroclinic effect at the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>A</mml:mi><mml:mo>−</mml:mo><mml:mi>C</mml:mi></mml:math>phase change in a chiral smectic liquid crystal

Abstract

When a smectic-$A$ phase is composed of chiral molecules, it exhibits an electroclinic effect, i.e., a direct coupling of molecular tilt to applied field. The pretransitional behavior of the electroclinic effect in the $A$ phase is used to study the critical behavior near the second-order, smectic-$A$---smectic-$C$ phase transition. This behavior is measured by monitoring the change in birefringence of a sample as the electroclinic effect causes a tilt of the molecules. A large pretransitional effect is measured, and constants describing the critical behavior are determined.