Molecular simulation study of polar order in orthogonal bent core smectic liquid crystals

TL;DR

This study uses Monte Carlo simulations to investigate phase transitions and polar order in orthogonal bent-core smectic liquid crystals, revealing local polar correlations and field-induced biaxial ordering.

Contribution

Introduces a simple molecular model and demonstrates the emergence of polar domains and phase transitions in bent-core liquid crystals through simulation.

Findings

Presence of local in-plane polar correlations in uniaxial smectic phase

Field enhances polar domain size and induces biaxial order-disorder transition

Phase transitions between uniaxial and biaxial smectic phases observed

Abstract

We explore the phase behavior and structure of orthogonal smectic liquid crystals consisting of bent-core molecules (BCMs) by means of Monte Carlo molecular simulations. A simple athermal molecular model is introduced that describes the basic features of the BCMs. Phase transitions between uniaxial and biaxial (antiferroelectric) orthogonal smectics are obtained. The results indicate the presence of local in-plane polar correlations in the uniaxial smectic phase. The macroscopic uniaxial-biaxial transformation is rationalized in terms of local polar correlations giving rise to polar domains. The size of these polar domains grows larger under the action of an external vector field and their internal ordering is enhanced, leading to field-induced biaxial order-disorder transitions.