Towards frustration of freezing transition in a binary hard-disk mixture

TL;DR

This paper investigates how binary hard-disk mixtures transition from ordered to disordered states as a function of size ratio and density, extending previous monodisperse freezing theories.

Contribution

It extends the understanding of freezing mechanisms from monodisperse to binary mixtures, identifying the critical diameter ratio affecting order formation.

Findings

For diameter ratios < 1.15, mixtures tend to form crystalline-like phases with increasing density.

For diameter ratios > 1.15, mixtures remain disordered regardless of density.

Structural and thermodynamic properties vary significantly with diameter ratio and packing fraction.

Abstract

The freezing mechanism, recently suggested for a monodisperse hard-disk fluid [Huerta et al., Phys. Rev. E, 2006, 74, 061106] is extended here to an equimolar binary hard-disk mixtures. We are showing that for diameter ratios, smaller than 1.15 the global orientational order parameter of the binary mixture behaves like in the case of a monodisperse fluid. Namely, by increasing the disk number density there is a tendency to form a crystalline-like phase. However, for diameter ratios larger than 1.15 the binary mixtures behave like a disordered fluid. We use some of the structural and thermodynamic properties to compare and discuss the behavior as a function of diameter ratio and packing fraction.