Reentrant Transitions in a Mixture of Small and Big Particles Interacting via Soft Repulsive Potential

TL;DR

This paper reports the first simulation observation of temperature-controlled reentrant phase transitions in a two-dimensional mixture of small and big particles with soft repulsive interactions, revealing complex entropy-driven behavior.

Contribution

It introduces the first simulation evidence of reentrant transitions in soft-repulsive particle mixtures, highlighting entropy effects on phase stability.

Findings

Reentrant transition from fluid to crystal and back to fluid with increasing temperature.

Solidification driven by entropy gain of small particles overcoming free energy costs.

Melting caused by increased particle interpenetration reducing entropic stabilization.

Abstract

We report the first observation of temperature-controlled reentrant transition in simulations of mixtures of small and big particles interacting via soft repulsive potential in 2D. As temperature increases, the system passes from a fluid mixture, to a crystal of big particles in a fluid of small particles and back to a fluid mixture. Solidification is driven by entropy gain of small particles which overcomes the free energy cost of confining big ones. Melting results from enhanced interpenetration of particles at high temperature which reduces the entropic forces that stabilize the crystal.