Dielectric properties of a ferroelectric nematic material: quantitative test of the polarization-capacitance Goldstone mode

TL;DR

This study uses dielectric spectroscopy to verify the polarization-capacitance Goldstone mode in ferroelectric nematic liquid crystals, clarifying previous measurement ambiguities and estimating dielectric constants.

Contribution

It provides a quantitative test of the polarization-capacitance Goldstone mode model in ferroelectric nematic materials, addressing prior measurement concerns.

Findings

Quantitative verification of Clark et al.'s model

Estimation of epsilon perpendicular~100 in NF phase

Clarification of dielectric measurement interpretations

Abstract

The recently discovered ferroelectric nematic (NF) liquid crystals (LC) have been reported to show an extraordinarily large value of the real part of the dielectric constant at low frequencies. However, it was argued by Clark et al in Physical Review Research 6, 013195 (2024) that what was measured was the capacitance of the insulating layer at LC/electrode surface and not that of the liquid crystal. Here we describe the results of dielectric spectroscopy measurements of an NF material in cells with variable thickness of the insulating layers. Our measurements quantitatively verify the model by Clark et al. Additionally, our measurements in cells with bare conducting indium tin oxide surface provide a crude estimate of epsilon perpendicular~100 in the NF phase.