Modelling the helical-flexo-electro-optic effect

TL;DR

This paper advances understanding of the helical-flexo-electro-optic effect by developing a perturbative and numerical approach to analyze the structure and dielectric influences, improving upon previous analytic models.

Contribution

It introduces a perturbative approximation and numerical methods to analyze the helical-flexo-electro-optic effect without previous assumptions about uniformity.

Findings

Dielectric behavior significantly affects tilt angle predictions.

Numerical methods reveal deviations from previous analytic models.

Elastic constants and dielectric anisotropy influence the electro-optic response.

Abstract

The helical-flexo-electro-optic effect shows interesting in-plane electro-optic switching behaviour due to flexoelectric coupling with applied electric fields. Previous understanding of the behaviour has been generally based on an analytic approach which makes certain assumptions about the uniformity of the helical structure and the induced tilt angle under field application. Here we remove these assumptions and develop a perturbative approximation to describe the structure in more detail. We also use a numerical method to investigate the behaviour in regimes where the perturbative approach is inappropriate. The impact of variation in elastic constants and dielectric anisotropy is investigated. We find that dielectric behaviour in particular can lead to substantial differences between the tilt angle obtained here and those obtained using previous analytic models.