Enhancement of nematic order and global phase diagram of a lattice model for coupled nematic systems

TL;DR

This paper uses an exactly solvable lattice model to explore how coupling between two nematic subsystems enhances nematic order and alters the phase diagram, with potential relevance to experimental systems involving ferroelectric nanoparticles in liquid crystals.

Contribution

It introduces an exactly solvable model for coupled nematic systems, revealing how interactions influence phase transitions and nematic order enhancement.

Findings

Nematic-isotropic transition temperature increases with inter-system coupling.

Coupling enhances nematic order across the phase diagram.

Results connect to experimental observations in nanoparticle-doped nematics.

Abstract

We use an infinite-range Maier-Saupe model, with two sets of local quadrupolar variables and restricted orientations, to investigate the global phase diagram of a coupled system of two nematic subsystems. The free energy and the equations of state are exactly calculated by standard techniques of statistical mechanics. The nematic-isotropic transition temperature of system A increases with both the interaction energy among mesogens of system B, and the two-subsystem coupling $J$. This enhancement of the nematic phase is manifested in a global phase diagram in terms of the interaction parameters and the temperature $T$. We make some comments on the connections of these results with experimental findings for a system of diluted ferroelectric nanoparticles embedded in a nematic liquid-crystalline environment.