Topological defects in solids with odd elasticity

TL;DR

This paper explores how odd elasticity, a non-conventional form of elasticity, affects topological defects in solids, revealing novel behaviors like defect self-propulsion and altered interactions, with implications for active materials.

Contribution

It introduces the concept of odd elasticity in solids, demonstrating its impact on defect behavior and interactions, supported by molecular dynamics simulations.

Findings

Odd elasticity modifies defect strain fields.

Dislocations can self propel via active core processes.

Odd elasticity can reverse dislocation pair stability.

Abstract

Crystallography typically studies collections of point particles whose interaction forces are the gradient of a potential. Lifting this assumption generically gives rise in the continuum limit to a form of elasticity with additional moduli known as odd elasticity. We show that such odd elastic moduli modify the strain induced by topological defects and their interactions, even reversing the stability of, otherwise, bound dislocation pairs. Beyond continuum theory, isolated dislocations can self propel via microscopic work cycles active at their cores that compete with conventional Peach-Koehler forces caused, for example, by an ambient torque density. We perform molecular dynamics simulations isolating active plastic processes and discuss their experimental relevance to solids composed of spinning particles, vortex-like objects, and robotic metamaterials.