Nat. Commun. 10, 4744 (2019)

Schools of fish can move in an organized manner because each fish tries to match its movements to its neighbours. As fish don’t necessarily lend themselves to controlled parameter studies, it is fortunate that the same collective effects that make a school of fish swim as one can also arise in synthetic systems. These make attractive experimental test beds of schooling dynamics — especially if they use readily available technology. Hayley Sohn and colleagues have now shown that skyrmions in liquid crystals can display collective effects similar to a school of fish.

figure a

under a Creative Commons licence (http://creativecommons.org/licenses/by/4.0/)

In their experiments, the skyrmions — stable topological structures — were formed in the director field of the liquid crystal. An oscillating electric field applied to the crystal cell broke the symmetry of the system and allowed the skyrmions to move of their own accord. The skyrmions interacted elastically with their neighbours, which led to collective effects — such as re-assembly or formation of chains and clusters.