Modulated nematic structures and chiral symmetry breaking in 2D

TL;DR

This study uses Monte Carlo simulations to explore how biaxial particles with complex interactions on a 2D lattice can spontaneously form chiral, modulated nematic phases, revealing insights into chiral symmetry breaking and phase transitions.

Contribution

It demonstrates the emergence of chiral symmetry breaking and modulated nematic phases in a 2D lattice model with quadrupolar and octupolar interactions, highlighting the role of anisotropic pair potentials.

Findings

Spontaneous chiral symmetry breaking from isotropic to chiral nematic phase.

Formation of ambidextrous chiral domains with a cholesteric phase.

First-order phase transition associated with the symmetry breaking.

Abstract

We have studied the properties of biaxial particles interacting via an anisotropic pair potential, involving second rank quadrupolar and third rank octupolar coupling terms, using Monte Carlo simulation. The particles occupy the sites of a 2D square lattice and the interactions are restricted to nearest neighbours. The system exhibits spontaneous chiral symmetry breaking from an isotropic phase to a chiral modulated nematic phase, composed of ambidextrous chiral domains. When two-fold axes of quadrupolar and octupolar tensors coincide this modulated phase appears to be the ambidextrous cholesteric phase of pitch comparable with a few lattice spacings, which can be regarded as a limiting case of the nematic twist bend phase. The associated phase transition is first-order.