Smectic C Model with Separate Order Parameters for the Layer thickness and The Optical Tilt Angle: Variation of The Layer Thickness in the Smectic C Phase

Abstract

Recently a model for the smectic A to smectic C transition has been proposed with separate order parameters for the optical tilt angle a and the quantity d/l, where d is the layer thickness and 1 the molecular length. Within the simplest Landau Theory for this type of model, and with the assumption that the system is near the smectic A - smectic C tricritical point, we find the simple result where σ=α/ϵ, ϵ=cos^−ld/l and d_A is the layer thickness in the A phase (O⩽σld/d_A is approximately linear.