Topologically Protected Steady Cycles in an Ice-Like Mechanical Metamaterial

Abstract

Competing ground states may lead to topologically constrained excitations such as domain walls or quasiparticles, which govern metastable states and their dynamics. Domain walls and more exotic topological excitations are well studied in magnetic systems such as artificial spin ice, in which nanoscale magnetic dipoles are placed on geometrically frustrated lattices, giving rise to highly degenerate ground states. We propose a mechanical spin-ice constructed from a lattice of floppy, bistable square unit cells. We compare the domain wall excitations that arise in this metamaterial to their magnetic counterparts, finding that new behaviors emerge in this overdamped mechanical system. By tuning the ratios of the internal elements of the unit cell, we control the curvature and propagation speed of internal domain walls. We change the domain wall morphology from a binary, strictly spin-like regime, to a more continuous, elastic regime. In the elastic regime, we inject, manipulate, and expel domain walls via textured forcing at the boundaries. The system exhibits dynamical hysteresis, and we find a first-order dynamical transition as a function of the driving frequency. We demonstrate a forcing protocol that produces multiple, topologically-distinct steady cycles, which are protected by the differences in their internal domain wall arrangements. These distinct steady cycles rapidly proliferate as the complexity of the applied forcing texture is increased, thus suggesting that such mechanical systems could serve as useful model systems to study multistability, glassiness, and memory in materials.

15 pages, 14 figures

References in corpus (10)

• Programmable Mechanical Metamaterials
• Bistable Auxetic Mechanical Metamaterials Inspired by Ancient Geometric Motifs
• Combinatorial Design of Textured Mechanical Metamaterials
• Geometric Frustration in Buckled Colloidal Monolayers
• Realizing Colloidal Artificial Ice on Arrays of Optical Traps
• Ice Rule and Emergent Frustration in Particle Ice and Beyond
• Order-by-disorder in the antiferromagnetic Ising model on an elastic triangular lattice
• Response evolution of mechanical metamaterials under architectural transformations
• Topology Restricts Quasidegeneracy in Sheared Square Colloidal Ice
• Classical topological order of the Rys F-model and its breakdown in realistic spin ice: Topological sectors of Faraday loops

Cited by in corpus (7)

• Emergent Disorder and Mechanical Memory in Periodic Metamaterials
• Generalizing multiple memories from a single drive: The hysteron latch
• Putting a spin on metamaterials: Mechanical incompatibility as magnetic frustration
• Macroscopic Magnetic Monopoles in a 3D-Printed Mechano-Magnet
• Breaking Mechanical Holography in Combinatorial Metamaterials
• Defect Positioning in Combinatorial Metamaterials
• Topological geometric frustration in a cube-surface artificial spin ice