Bulk and surface dominated phenomena and the formation of pentagonal structures in 2-D strongly coupled finite dust clusters

This paper explores the prevalence of size-dependent aspects in the context of dust clusters with the help of Molecular Dynamics (MD) simulations in two dimensions. The transition from macroscale (identified by the dominance of the number of dust particles in bulk) to microscale (where the number of particles on the surface dominates) is explored systematically. The dust particles organize in a multi-ringed structure when confined in the 2-D plane. The ring size and the number of rings increase with the increasing number of dust particles. Interestingly, the formation of an additional ring is always preceded by structures with a pentagonal symmetry in the core. A detailed study of this formation has been investigated under various symmetries of the boundary condition and different values of the shielding potential.