Self-pinning and Self-climbing of skyrmion dislocations through topological characterization: Lattice mechanics of deformable quasiparticles

Skyrmions are emergent quasiparticles in ferromagnets possessing topologically identified unique dynamics, stability, and deformability. They self-assemble into skyrmion lattices whose collective behaviors are central to both fundamental understandings and spintronics applications. However, in contrast to atomic crystals, the lattice mechanics in skyrmion lattices, where lattice defect dynamics mediate macroscopic deformations, remain elusive. Here, we revealed unconventional defect dynamics in skyrmion lattices, including self-pinning and self-climbing of dislocations accompanied by large skyrmion deformations with topologically protected transitions from a single skyrmion to half-skyrmions. Our phase-field simulations demonstrate that external field dependent skyrmion deformability fundamentally alters lattice defect behaviors from conventional atom-like dislocation glide to the phenomena unique to topological quasiparticles. These behaviors are successfully revealed by topological characterization and described by strain analysis. This study not only provides critical insight into spintronics engineering for skyrmion-based devices but also establishes a foundation for a new class of mechanics, “quasiparticle lattice mechanics”.