Coulomb bicrystals of species with identical charge-to-mass ratios

Structures of cold bicomponent Coulomb systems of particles with identical charge-to-mass ratios and common oscillation frequency in a spherical harmonic potential are studied by molecular dynamics simulations with up to 10(6) particles. For most initial conditions and cooling rates, the final state becomes a completely mixed core surrounded by a set of nearly degenerated double shells of separate species. For an equal amount of the two species, it is found that the ground state for larger systems consists of a simple cubic structured core surrounded by outer double-shell structures.