Structure and phase behavior of a two-dimensional system with core-softened and long-range repulsive interactions

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Abstract

The structure and phase behavior of a two-dimensional system with purely repulsive core-softened and long-range interactions are studied using Monte Carlo computer simulations. The pair interactions are of the form, u(r)=4epsilon[(sigma/r)(12)-(sigma/r)(6)]+epsilon'(sigma/r)(3), with the energy parameter, epsilon'=(root6/9)epsilon chosen to give a stationary point of inflection in the pair potential at r=6(1/6)sigma. This potential approximates the effective interparticle interactions for a two-dimensional dipolar system in a strong field aligned perpendicular to the plane. The low-temperature portion of the phase diagram is sketched out, and the static properties of the various phases are analyzed in some detail. At low temperatures a variety of interesting states are in evidence, including: fluids with chainlike, striped, and 6-10 sided polygon structural motifs; low-density and high-density triangular crystalline phases; and defective Kagome lattices. It is shown that clustering is driven by the presence of the repulsive shoulder in the pair potential. Other features, such as the presence of a disordered phase with a network structure, are due to the long-range (1/r(3)) repulsive tail in the potential. The relevance of the simulation results to experimental work, including materials synthesis, is briefly discussed.

Original languageEnglish
Article number061506
Pages (from-to)-
Number of pages8
JournalPhysical Review E - Statistical, Nonlinear and Soft Matter Physics
Volume68
Issue number6
DOIs
Publication statusPublished - Dec 2003

Keywords

  • CRYOGENIC ELECTRON-MICROSCOPY
  • DIPOLAR CHAINS
  • STRIPE PHASES
  • 2 DIMENSIONS
  • TRANSITION
  • FERROFLUIDS
  • PARTICLES
  • WATER

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