Bivalent defect configurations in inhomogeneous nematic shells

TL;DR

This paper theoretically investigates the configurations and energetics of nematic liquid crystal shells with two defect pairs, revealing phase transitions influenced by shell thickness and inhomogeneity, and explaining experimental observations.

Contribution

It introduces a phase diagram for defect configurations in inhomogeneous nematic shells, linking shell properties to defect behavior and transitions.

Findings

Abrupt transitions between defect configurations based on shell parameters

Phase diagram mapping stability regions of defect states

Agreement with experimental defect transition observations

Abstract

We present a theoretical study of the director fields and energetics of nematic liquid crystal shells with two pairs of surface defects. The pairs of defects can undergo abrupt transitions between a configuration of maximum separation to at state in which the defects are confined to the thinnest hemisphere. We construct a phase diagram that maps out the stability and coexistence of these two configurations as a function of shell thickness and thickness inhomogeneity. Our results compare favorably with the experimentally observed transitions in nematic double emulsion droplets and explain their hysteretic character.