Mechanisms of Skyrmion and Skyrmion Crystal Formation from the Conical Phase
mediaposted on 2020-03-26, 14:41 authored by Tae-Hoon Kim, Haijun Zhao, Ben Xu, Brandt A. Jensen, Alexander H. King, Matthew J. Kramer, Cewen Nan, Liqin Ke, Lin Zhou
Real-space topological magnetic structures such as skyrmions and merons are promising candidates for information storage and transport. However, the microscopic mechanisms that control their formation and evolution are still unclear. Here, using in situ Lorentz transmission electron microscopy, we demonstrate that skyrmion crystals (SkXs) can nucleate, grow, and evolve from the conical phase in the same ways that real nanocrystals form from vapors or solutions. More intriguingly, individual skyrmions can also “reproduce” by division in a mitosis-like process that allows them to annihilate SkX lattice imperfections, which is not available to crystals made of mass-conserving particles. Combined string method and micromagnetic calculations show that competition between repulsive and attractive interactions between skyrmions governs particle-like SkX growth, but nonconservative SkX growth appears to be defect mediated. Our results provide insights toward manipulating magnetic topological states by applying established crystal growth theory, adapted to account for the new process of skyrmion mitosis.
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crystal growth theorynanocrystals formmechanismmitosis-like processparticle-like SkX growthinformation storagemicromagnetic calculations showstring methodconical phaseConical Phase Real-space topologicaltopological statesnonconservative SkX growthskyrmion mitosisLorentz transmission electron microscopymass-conserving particlesSkX lattice imperfectionsSkyrmion Crystal Formationskyrmion crystals