Composite Dislocations in Smectic Liquid Crystals

Abstract

Smectic liquid crystals are charcterized by layers that have a preferred uniform spacing and vanishing curvature in their ground state. Dislocations in the smectics play an important role in phase nucleation, layer reorientation, and dynamics. Typically modeled as possessing one line singularity, the layer structure of a dislocation leads to a diverging compression strain as one approaches the defect center, suggesting a large, elastically determined melted core. However, it has been observed that for large charge dislocations, the defect breaks up into two disclinations [C. E. Williams, Philos. Mag. 32, 313 (1975)]. Here we investigate the topology of the composite core. Because the smectic cannot twist, transformations between different disclination geometries are highly constrained. We demonstrate the geometric route between them and show that despite enjoying precisely the topological rules of the three-dimensional nematic, the additional structure of line disclinations in three-dimensional smectics localizes transitions to higher-order point singularities.

5 pages, 3 figures

References in corpus (1)

• Smectics: Symmetry Breaking, Singularities, and Surfaces

Cited by in corpus (10)

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• Smectic Layering: Landau theory for a complex-tensor order parameter
• Computing with non-orientable defects: nematics, smectics and natural patterns
• Network topology of interlocked chiral particles
• Colloidal smectics in button-like confinements: experiment and theory
• Layer topology of smectic grain boundaries
• Dislocations and Fibrations: The Topological Structure of Knotted Smectic Defects