Emergent Self-propulsion of Skyrmionic Matter in Synthetic Antiferromagnets

Abstract

Self-propulsion plays a crucial role in biological processes and nanorobotics, enabling small systems to move autonomously in noisy environments. Here, we theoretically demonstrate that a bound skyrmion-skyrmion pair in a synthetic antiferromagnetic bilayer can function as a self-propelled topological object, reaching speeds of up to a hundred million body lengths per second--far exceeding those of any known synthetic or biological self-propelled particles. The propulsion mechanism is triggered by the excitation of back-and-forth relative motion of the skyrmions, which generates nonreciprocal gyrotropic forces, driving the skyrmion pair in a direction perpendicular to their bond. Remarkably, thermal noise induces spontaneous reorientations of the pair and momentary reversals of the propulsion, mimicking behaviors observed in motile bacteria and microalgae.

Includes End Matter and Supplemental Material (total: 15 pages)

References in corpus (20)

• Advances in the Physics of Magnetic Skyrmions and Perspective for Technology
• Spontaneous Skyrmion Ground States in Magnetic Metals
• Thermally Driven Ratchet Motion of Skyrmion Microcrystal and Topological Magnon Hall Effect
• Dynamics of domain walls in magnetic nanostrips
• Physical foundations and basic properties of magnetic skyrmions
• Skyrmion Qubits: A New Class of Quantum Logic Elements Based on Nanoscale Magnetization
• Inertia, diffusion and dynamics of a driven skyrmion
• Breathing modes of confined skyrmions in ultrathin magnetic dots
• Selective and Collective Actuation in Active Solids
• Brownian reservoir computing realized using geometrically confined skyrmions
• Fast current-induced skyrmion motion in synthetic antiferromagnets
• Spontaneous magnetic skyrmions in single-layer CrInX3(X=Te, Se)
• Magnetic skyrmion braids
• Schools of skyrmions with electrically tunable elastic interactions
• Skyrmion Qubits: Challenges For Future Quantum Computing Applications
• Coupled skyrmion breathing modes in synthetic ferri- and antiferromagnets
• Mesoscale phase separation of skyrmion-vortex matter in chiral magnet-superconductor heterostructures
• Chiral Skyrmions Interacting with Chiral Flowers
• Robust formation of nanoscale magnetic skyrmions in easy-plane thin film multilayers with low damping
• All optical control of bubble and skyrmion breathing