Arrested coarsening and large density fluctuations in driven particle mixtures in two dimensions

Using molecular dynamics simulations, we study a driven, nonadditive binary mixture of spherical particles confined to move in two dimensions and immersed in an explicit solvent consisting of point particles with purely repulsive interactions. We show that, without a drive, the mixture of spherical particles phase separates and coarsens with kinetics consistent with an Ising-like conserved dynamics. Conversely, when the drive is applied, the coarsening is arrested and the system develops large density fluctuations. We show that the drive creates domains of a characteristic size which decreases with an increasing force. Furthermore, we find that these domains are anisotropic and can be oriented either parallel or perpendicular to the drive direction. Finally, we connect our findings to existing theories of strongly-driven systems, pointing out the importance of introducing the explicit solvent particles to break the Galilean invariance of the system.

Automated summary

Using molecular dynamics simulations, the researchers studied a driven, nonadditive binary mixture of spherical particles in a two-dimensional explicit solvent. They found that without a drive, the mixture phase separates and coarsens with an Ising-like conserved dynamics. However, when a drive is applied, coarsening is arrested and large density fluctuations occur, with domains of characteristic size forming. The researchers also discovered that these domains are anisotropic and can be oriented parallel or perpendicular to the drive direction. They emphasize the importance of introducing explicit solvent particles to break the Galilean invariance of the system.