Structure of two-dimensional electron clusters with various shapes, at low temperatures

Abstract

The molecular dynamics method is used to study the structure of two-dimensional clusters that can be created in electronic systems above the surface of superfluid helium, using triangular, square, hexagonal and round holding electrode geometries. Clusters with a fixed surface density of 108 cm−2, but different numbers of particles (from 3 to 406) are considered. The spatial configurations of particles in clusters are calculated corresponding to a temperature of 10−2 K. The shape of the cluster significantly affects the arrangement of the electrons inside. If the symmetry of the cluster is consistent with the triangular symmetry of the electronic crystal, then for some numbers of particles, clusters with ideal defect-free packing are possible; otherwise, the clusters contain defects. An additional external field applied to the cluster significantly changes the configuration of its particles.