Generic properties of a quasi-one-dimensional classical Wigner crystal
journal contributionposted on 17.07.2013 by G. Piacente, I.V. Schweigert, Joseph Betouras, F.M. Peeters
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We studied the structural, dynamical properties and melting of a quasi-one-dimensional system of charged particles, interacting through a screened Coulomb potential. The ground-state energy was calculated and, depending on the density and the screening length, the system crystallizes in a number of chains. As a function of the density (or the confining potential), the ground state configurations and the structural transitions between them were analyzed both by analytical and Monte Carlo calculations. The system exhibits a rich phase diagram at zero temperature with continuous and discontinuous structural transitions. We calculated the normal modes of the Wigner crystal and the magnetophonons when an external constant magnetic field B is applied. At finite temperature the melting of the system was studied via Monte Carlo simulations using the modified Lindemann criterion (MLC). The melting temperature as a function of the density was obtained for different screening parameters. Reentrant melting as a function of the density was found as well as evidence of directional dependent melting. The single-chain regime exhibits anomalous melting temperatures according to the MLC and as a check we study the pair-correlation function at different densities and different temperatures, which allowed us to formulate a different melting criterion. Possible connection with recent theoretical and experimental results are discussed and experiments are proposed.