From Crystals to Disordered Crystals: A Hidden Order-Disorder Transition

TL;DR

This paper uncovers a transition from crystalline to disordered crystalline states in sphere packings, revealing unique properties and critical behaviors near close packing, driven by structural order and density.

Contribution

It introduces the concept of a hidden order-disorder transition in static sphere packings, highlighting properties of disordered crystals distinct from regular crystals.

Findings

Disordered crystals exhibit properties different from crystalline states.

The transition approaches the close packing of spheres, showing singular behavior.

Elastic moduli and coordination number depend on pressure uniquely near the transition.

Abstract

We find an order-disorder transition from crystals to disordered crystals for static packings of frictionless spheres. While the geometric indicators are mostly blind to the transition, disordered crystals already exhibit properties apart from crystals. The transition approaches the close packing of hard spheres, giving rise to the singularity of the close packing point. We evidence that both the transition and properties of disordered crystals are jointly determined by the structural orders and density. Near the transition, the elastic moduli and coordination number of disordered crystals show particular pressure dependence distinct from both crystals and jammed solids.