Origins of polar order in the ferroelectric nematic phase*

We have carried out atomistic simulation studies of the recently described ferroelectric nematic (N_F) phase [1] in an effort to identify the key features of molecular interactions and correlations responsible for polar order in N_F materials. Comparative simulations of polar and nonpolar states of the N_F mesogen RM734 reveal distinct polarity-dependent intermolecular correlations and characteristic polar and antipolar pair association motifs, and demonstrate that the polar state of RM734 is stabilized by short-range electrostatic interactions. This electrostatic stabilization mechanism is absent in closely related compounds that lack the N_F phase, indicating a sensitive dependence of polar ordering tendency on molecular shape and charge distribution. These results imply that polar order in the N_F phase results from a subtle interplay of specific short-range electrostatic and steric interactions.
[1] “First-Principles Demonstration of Ferroelectricity in a Thermotropic Nematic Liquid Crystal: Spontaneous Polar Domain Formation and Spectacular Electro-Optics”, X. Chen et al. PNAS 2020
Author for Correspondence: matthew.glaser@colorado.edu