Domain Structures of Smectic Films Formed by Bent-Shaped Molecules

TL;DR

This paper develops a Landau model to explain the domain structures in smectic films formed by achiral bent-shaped molecules, highlighting the interplay of polarization, tilt, and chirality.

Contribution

It introduces a simple theoretical framework capturing the coupling of order parameters that explains observed domain structures in these smectic phases.

Findings

The model predicts three types of ordering related to polarization, tilt, and chirality.

Coupling of order parameters leads to specific domain structures.

Experimental observations are explained by the model's predictions.

Abstract

We formulate a simple Landau type model describing macroscopic behaviour recently discovered new smectic phases composed of achiral bent-shaped molecules. Films of such smectics exhibit three types of ordering related to dipole polarization, molecular tilt, and chirality. However due to specific third order coupling of the order parameters these three types of symmetry-breaking are not independent ones, and this fact leads to specific domain structures really observed in experiments.