Effects of edge pinning on the melting transition of a two-dimensional solid

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Abstract
A molecular-dynamics simulation was used to examine how the pinning of edge particles affects the nature and the dynamics of the melting transition for a two-dimensional solid. The system consisted of 256 particles interacting through an inverse-power of r repulsive potential. These particles were confined by periodic boundary conditions in one direction and by two pinned walls (lines of particles) in the other. The results are compared to a system of 256 particles with the usual periodic boundary conditions. The pinned walls shifted the transition temperature and substantially increased the temperature range over which melting takes place. The fluctuations found in the periodic system are significantly reduced by the presence of the walls. Furthermore, these walls tend to stabilize the interface between the solidlike and liquidlike domains, and produce a spatially separated two-phase system. The structural effects of the walls were found to propagate relatively far into the system. The existence of pinned walls has important effects on both the thermodynamic functions and the structural properties of the system.