Screw dislocation interaction in smectic-A liquid crystals in an anharmonic approximation

TL;DR

This paper investigates the interaction forces between screw dislocations in smectic-A liquid crystals using an anharmonic elastic energy model, revealing attraction at small separations and repulsion at larger distances.

Contribution

It introduces an anharmonic correction to the elastic energy density to analyze dislocation interactions, highlighting differences from solid materials.

Findings

Dislocations attract at small separations

Dislocations repel at larger separations

Interaction energy differs from solid dislocation cases

Abstract

The interaction of two screw dislocations in smectic-A liquid crystals is treated using an anharmonic correction to the elastic energy density. In the present contribution the elastic energy and the force between two screw dislocations is evaluated and discussed. For screw dislocations with both parallel and opposite Burgers vectors there is an attraction of dislocations for their small separations while for greater separations there is a repulsion. It can be explained by dominating terms in interaction energy which do not depend on signs of dislocations. In this way, the interaction energy of screw dislocations in smectic A liquid crystal within an anharmonic approximation differs with respect to the case of screw dislocations in solids.