Nonequilibrium processes in repulsive binary mixtures

Area of Science:

• Classical statistical mechanics
• Soft matter physics
• Computational condensed matter physics

Background:

• Binary mixtures at infinite temperature behave as ideal gases.
• Rapid cooling (quenching) to zero temperature induces ordering processes.
• Interactions between particles significantly influence system behavior.

Purpose of the Study:

• To investigate the ordering processes in classical, 3D, purely repulsive binary mixtures after rapid cooling.
• To determine how tuning inter-species interactions affects the type of ordering.
• To explore the universality of this phenomenon for repulsive potentials.

Main Methods:

• Simulations of classical, three-dimensional, purely repulsive binary mixtures.
• Instantaneous quenching from infinite temperature (ideal-gas state) to zero temperature.
• Analysis of ordering processes as a function of inter-species repulsion strength.

Main Results:

• Two distinct ordering processes were observed: chemical ordering (unmixing) and spontaneous crystallization.
• Strong inter-species repulsion promotes unmixing, leading to chemical ordering.
• Weak inter-species repulsion promotes spontaneous crystallization, maintaining chemical homogeneity.

Conclusions:

• The type of ordering in rapidly cooled binary mixtures is controllable by inter-species interactions.
• A transition in the potential-energy landscape topography underlies the dual ordering behavior.
• The observed dual-type behavior is general for repulsive pair-interaction potentials.