Mesoscopic two-dimensional electron crystals in single and double layers

We present results of Monte-Carlo simulations for finite 2D single and bila yer systems. Strong Coulomb correlations lead to arrangement of particles i n configurations resembling a crystal lattice. For binary layers, there exi sts a particularly rich variety of lattice symmetries which depend on the i nterlayer separation d. We demonstrate that in these mesoscopic lattices th ere exist two fundamental types of ordering: radial and orientational. The dependence of the melting temperature on d is analyzed, and a stabilization of the crystal compared to a single layer is found.