Collective depinning of driven monolayer active colloidal particles with magnetic dipole and Mie-type interactions

Abstract

We report Langevin simulations on the collective depinning of driven monolayer active colloidal particles over the disordered substrate. The active colloidal particles are modeled as Janus particles interacting with magnetic dipole and Mie-type potentials. On increasing the Mie-type potential exponent , we find a peak of critical pinning force at . Above the depinning, there are living islands when the exponent is less than , and they disappear once is larger than . Further increasing the exponent will lead to moving crystal structures above the depinning. Moreover, the peak of critical pinning force occurs at a weaker strength of magnetic-dipole interaction as is increased to be a larger value, and it disappears as is further increased over . Finally, the critical pinning force remains basically unchanged with the strength of Mie-type potential, except for the system of , where the critical pinning force decreases with the strength of Mie-type potential. Our results are helpful to understand the formation of self-organisation in electromagnetic interaction biological systems driven by external field.