Order and disorder in hard-sphere packings

We study the crystallisation of hard-sphere systems and compare the resulting packings with packings belonging to the stable branch of the phase diagram. This comparison is done by studying the distribution of a local bond order parameter which gives precise information on the structure and allows to detect without ambiguity the presence of fcc or hcp crystallisation in the packing. We have found, as expected, that the fcc symmetry is more stable than the hcp symmetry in crystallised systems. Furthermore, the fraction of hcp clusters in the system decreases as the propensity to crystallise increases. The method developed here for hard-sphere systems can be applied to any kind of soft-sphere potential systems.