LAUSR

The molecular dynamics method is used to study the melting of two-dimensional clusters that can form in electronic systems above the surface of superfluid helium with the help of triangular, square, hexagonal and round holding electrodes. Clusters with a fixed surface density of 108 cm−2, but different numbers of particles (from 3 to 406), are considered. It is shown that in defect-free clusters, the transition to a disordered state occurs abruptly and the melting point, Тmelt, is easy to determine. The dependence of Тmelt on the cluster size is observed for clusters with N   100, a triangular lattice with defects near the boundary is observed. In round clusters, electrons begin to move easily in the angular direction at rather low temperatures, but the “radial melting” temperature is consistent with the melting point of small square clusters. In the presence of defects, the transition to a disordered state begins from the defect region and gradually spreads to the entire cluster. There is no clear definition of the melting point in this scenario.