Phase separation and crystallisation of polydisperse hard spheres

TL;DR

This paper investigates how polydisperse hard spheres undergo phase separation into two crystalline solid phases when their polydispersity exceeds about 8%, highlighting the limits of crystallization in such systems.

Contribution

It demonstrates that high polydispersity leads to phase separation into two narrow-polydispersity crystalline phases, a phenomenon not previously well understood.

Findings

Polydispersity above 8% causes phase separation into two solid phases.

Single solid phase cannot tolerate polydispersity above 8%.

Glass transition may prevent experimental observation of this phase separation.

Abstract

Hard spheres with a polydispersity above approximately 8% are shown to crystallise into two phase-separated solid phases. A polydispersity above 8% is too large to be tolerated by a single solid phase but phase separation produces two fractions with polydispersities sufficiently narrow to allow them to crystallise. It may not be possible to observe this in experiment due to the intervention of a glass transition.