Dynamics of driven Janus particles with pure repulsive interactions over obstacle arrays in active bath

Using Langevin simulations, we study the dynamics of Janus particles with pure repulsive interactions, which are driven through obstacles in an active bath. We find a finite critical threshold for the driving force, below which the average velocity of Janus particles is zero. This is quite different from the case of thermal noise. Above the critical threshold, a nonlinear relationship between the average velocity of Janus particles and the driving force is found, and moving clusters are observed when the obstacle stiffness or the strength of repulsive interaction between Janus particles is small enough. These clusters will disperse as the obstacle stiffness or the strength of repulsive interaction between Janus particles increases. Our results are consistent with recent single-particle studies (Liu et al. in Phys Rev Lett 124:158001, 2020; Ye et al. in Soft Matter 16:4655, 2020), which demonstrate that the effective interaction between passive particles in an active bath depends on the external constraints suffered by the passive particles. This study not only helps to reveal the mechanism of dynamic ordering in active matter, but also provides a tool for regulating the effective interaction between passive particles in an active bath.