Micro-phase separation breaks hyperuniformity of jammed solids*

Maximally random jammed (MRJ) packings of hard spheres are conjectured to be hyperuniform. When density increases away from the MRJ point, it was found that the randomly jammed states gradually lose the hyperuniformity. A possible explanation is the growth of the structural order, i.e., the system becomes the mixture of order and disorder phases when density increases. However, it remains unclear whether this is the case in polydisperse systems. To clarify the picture, we numerically study polydisperse jammed states in two dimensions by quickly compressing supercooled hard disk liquids from different densities and by quickly quenching high temperature states of soft particles with repulsions. Upon the increase of density, we find a tendency of micro-phase separation (MPS) in both types of systems. In the presence of MPS, the spectral density χ(q) of dense packings of hard disks becomes flater and keeps decreasing in the q→0 limit, distinct from those with conventional phase separations. Furthermore, by comparing the results with soft particle states with similar degrees of MPS, we find that the MPS is responsible for the flattening of χ(q) in the q→0 limit.