Dimensionality effects in dipolar fluids

TL;DR

This study uses density functional theory to explore how reducing dimensionality affects phase transitions and ferroelectric ordering in dipolar fluids confined to a plane, revealing complex behaviors compared to 3D and 2D systems.

Contribution

It provides a detailed theoretical analysis of phase behavior in quasi-two-dimensional dipolar fluids, highlighting the effects of dimensionality on ferroelectric transitions.

Findings

Identification of first- and second-order isotropic-to-ferroelectric transitions.

Comparison of phase behavior across 3D, slab-like, and 2D systems.

Prediction of tricritical points related to ferroelectric ordering.

Abstract

Using classical density functional theory (DFT) in a modified mean-field approximation we investigate the fluid phase behavior of quasi-two dimensional dipolar fluids confined to a plane. The particles carry three-dimensional dipole moments and interact via a combination of hard-sphere, van-der-Waals, and dipolar interactions. The DFT predicts complex phase behavior involving first- and second-order isotropic-to-ferroelectric transitions, where the ferroelectric ordering is characterized by global polarization within the plane. We compare this phase behavior, particularly the onset of ferroelectric ordering and the related tricritical points, with corresponding three-dimensional systems, slab-like systems (with finite extension into the third direction), and true two-dimensional systems with two-dimensional dipole moments.