ABSTRACT
The role of defects in the melting transition of a bilayer dust plasma crystal with vertical alignment is studied using Langevin molecular dynamics simulations. Two types of defects are considered: (i) point defects and dislocations and (ii) additional particles which are placed below and above the bilayer crystal (i.e., the so-called strong defects). It is shown that the presence of point defects and a few dislocations does not change the two-step melting scenario previously found for nondefect bilayer crystals. This contrast with the influence of the strong defects which leads to a substantial increase of the kinetic energy of particles and to local heating of the bilayer dust crystal.
ABSTRACT
Melting of two-dimensional (2D) clusters of classical particles is studied using Brownian dynamics and Langevin molecular dynamics simulations. The particles are confined either by a circular hard wall or by a parabolic external potential and interact through a dipole or a screened Coulomb potential. We found that, with decreasing strength of the interparticle interaction, clusters with a short-range interparticle interaction and confined by a hard wall exhibit a reentrant behavior in its orientational order.
