Electrically Driven Formation and Dynamics of Skyrmionic Solitons in Chiral Nematics

Skyrmions are continuous but topologically nontrivial field configurations that behave like particles. They play an important role in fields ranging from condensed matter to nuclear physics. Realizing and manipulating different kinds of motions of skyrmions are still great challenges. Here, three-dimensional skyrmions, in the form of double-twist tori terminated on two topological point defects called "torons,"are produced in chiral nematic liquid crystals with varied helical pitches. The spontaneous formation of skyrmions and high-degree multiskyrmion configurations called "skyrmion bags"are characterized by polarizing microscopy. The skyrmions show anomalous diffusion in the equilibrium state and perform collective directional motion driven by fluid flows, with a velocity controllable by electric fields and surface anchoring. They can be utilized as vehicles for microcargo transport. We also show that skyrmions can collide and form clusters with tunable shape, anisotropy, and fractal dimension.