Nonlinear screening of high-Z grains and the formation of Coulomb latticesin colloidal plasmas

Liquid-solid phase transitions in colloidal plasmas are studied within the Yukawa model with nonlinearly screened effective potentials. It is shown, t hat there is a minimal charge asymmetry needed for the crystallization of a Coulomb lattice and its value depends on the packing fraction of the collo idal component. The smaller the packing fraction, the higher the charge asy mmetry, and, respectively, the stronger the coupling in the colloidal compo nent must be: in order to reach the solid stare. (C) 1999 Published by Else vier Science B.V. All rights reserved.