Mobility-induced phase separation in a binary mixture of active Brownian particles.

Area of Science:

• Soft Matter Physics
• Statistical Mechanics
• Computational Physics

Background:

• Active matter systems exhibit unique collective behaviors driven by self-propulsion.
• Phase separation is a fundamental phenomenon in condensed matter physics.
• Binary mixtures introduce complexity compared to monocomponent systems.

Purpose of the Study:

• To investigate mobility-induced phase separation in a 2D binary mixture of active soft Brownian particles.
• To characterize the structural and dynamic properties of coexisting phases.
• To compare the behavior of binary mixtures with monocomponent systems.

Main Methods:

• Brownian dynamics simulations were employed.
• Non-additive Weeks-Chandler-Andersen potentials were used to model particle interactions.
• Analysis included radial distribution functions, hexatic order parameter, and mean-square displacement.

Main Results:

• The high-density coexisting state in the binary mixture is spatially disordered and liquid-like.
• Both low- and high-density coexisting states in the binary system show diffusive behavior at long times.
• The monocomponent system's solid-like state also exhibits diffusive behavior due to active topological defects.

Conclusions:

• Active soft particle binary mixtures display distinct phase separation behaviors compared to monocomponent systems.
• The high-density phase in binary mixtures is characterized by liquid-like dynamics.
• Active topological defects play a crucial role in the dynamics of dense active matter systems.