The structure of the hard sphere solid

TL;DR

This paper investigates the entropy differences among dense sphere packings, revealing that the hexagonal close-packed (HCP) structure exhibits higher entropy near densest packing due to less constrained neighbor motions.

Contribution

It demonstrates that near densest packing, the HCP structure has higher entropy than other packings, based on correlation analysis of sphere motions.

Findings

HCP yields higher entropy near densest packing

Neighbor motion correlations differ among structures

Random motion impinges less in HCP

Abstract

We show that near densest-packing the perturbations of the HCP structure yield higher entropy than perturbations of any other densest packing. The difference between the various structures shows up in the correlations between motions of nearest neighbors. In the HCP structure random motion of each sphere impinges slightly less on the motion of its nearest neighbors than in the other structures.