The ground state configurations and the ‘‘normal’’ mode spectra of a quasi-one-dimensional binary system of charged particles interacting through a screened Coulomb potential are presented. The minimum energy configurations were obtained analytically and independently through molecular dynamic simulations. A rich variety of ordered structures was found as a function of the screening parameter, the particle density, and the ratio between the charges of the distinct types of particles. Continuous and discontinuous structural transitions as well as an unexpected symmetry breaking in the charge distribution are observed when the density of the system is changed. For nearly equal charges, we found a disordered phase where a mixing of the two types of particles occurs. The phonon dispersion curves were calculated within the harmonic approximation for the one- and two-chain structures.

• Received 22 October 2007

DOI:https://doi.org/10.1103/PhysRevB.77.014112