Should “lane formation” occur systematically in driven liquids and colloids?

We report on nonequilibrium molecular dynamics simulations of binary mixtures of particles in a color field. Both nonequilibrium molecular dynamics and Brownian dynamics generally assume that the mechanical noise is of thermal origin only and that, at a given temperature, its amplitude remains constant however strong the applied field is. We show that this postulate systematically results in the strong ordering of particles into lanes. By applying a nonequilibrium molecular dynamics method which does not exert any constraint on the noise amplitude, we show that releasing this constraint prevents the systematic "lane formation" from occurring. We observe the onset of density inhomogeneities and jamming instead. This behavior is reminiscent of the shear-thickening regime observed experimentally on colloidal suspensions and in simulations taking into account hydrodynamic interactions.