Dislocation Dynamics in an Anisotropic Stripe Pattern

TL;DR

This paper investigates how dislocations move within anisotropic stripe patterns in nematic liquid crystals, revealing power-law behaviors in domain evolution and highlighting the effects of anisotropy on defect dynamics.

Contribution

It provides new insights into dislocation dynamics in anisotropic systems, specifically quantifying the power-law evolution of domain features after a rapid voltage change.

Findings

Dislocation density decays as t^{-1/3}

Domain wall length grows as t^{1/3}

Total domain wall length decays as t^{-1/5}

Abstract

The dynamics of dislocations confined to grain boundaries in a striped system are studied using electroconvection in the nematic liquid crystal N4. In electroconvection, a striped pattern of convection rolls forms for sufficiently high driving voltages. We consider the case of a rapid change in the voltage that takes the system from a uniform state to a state consisting of striped domains with two different wavevectors. The domains are separated by domain walls along one axis and a grain boundary of dislocations in the perpendicular direction. The pattern evolves through dislocation motion parallel to the domain walls. We report on features of the dislocation dynamics. The kinetics of the domain motion are quantified using three measures: dislocation density, average domain wall length, and the total domain wall length per area. All three quantities exhibit behavior consistent with power law evolution in time, with the defect density decaying as $t^{-1/3}$, the average domain wall length growing as $t^{1/3}$, and the total domain wall length decaying as $t^{-1/5}$. The two different exponents are indicative of the anisotropic growth of domains in the system.