Structural, dynamical and melting properties of two-dimensional clusters of complex plasmas

Abstract

The static and dynamical properties of two-dimensional mesoscopic clusters of equally charged classical particles are investigated through the Monte Carlo simulation technique. The particles are confined by an external harmonic potential. The ground-state configuration and the position of the geometry induced defects are investigated as a function of the inter-particle interaction (Coulomb, dipole, logarithmic and screened Coulomb). The eigenmodes are investigated and the corresponding divergence and rotor are calculated which describe the 'shearlike' and 'compression-like' modes, respectively. The melting behaviour is found to be strongly influenced by the inter-particle interaction potential: a small cluster with a short-range interaction melts earlier than one with long-range interaction. The melting temperature is related to the energy barriers between the ground state and the metastable states. For larger clusters, the melting scenario changes and is strongly influenced by the location of the topological defects.