Two-Dimensional Melting of two- and three-component mixtures

TL;DR

This study investigates the melting behaviors of two- and three-component mixtures of hard polygons and disks in two dimensions, revealing universal criteria for phase transitions and the possibility of eutectic crystallization at higher densities.

Contribution

It establishes universal melting criteria for 2D mixtures and shows that mixtures can have different melting pathways than their pure components.

Findings

Mixtures can crystallize at higher densities than pure components.

Universal defect density thresholds for melting transitions.

Melting pathways can differ from those of individual components.

Abstract

We elucidate the interplay between diverse two-dimensional melting pathways and establish solid/hexatic and hexatic/liquid transition criteria via the numerical simulations of the melting transition of two- and three-component mixtures of hard polygons and disks. We show that a mixture's melting pathway may differ from its components and demonstrate eutectic mixtures that crystallize at a higher density than their pure components. Comparing the melting scenario of many two- and three-component mixtures, we establish universal melting criteria: the solid and hexatic phases become unstable as the density of topological defects respectively overcomes $\rho_{d,{\rm s}} \simeq 0.046$ and $\rho_{d,{\rm h}}\simeq 0.123$.