Dislocationmediated melting near isostructural critical points
Abstract
We study the interplay between an isostructural critical point and dislocationmediated twodimensional melting, using a combination of Landau and continuum elasticity theory. If dislocations are excluded, coupling to the elastic degrees of freedom leads to meanfield critical exponents. When dislocations are allowed, modified elastic constants lead to a phase buried in the solid state near the critical point. Consistent with a proposal of Bladon and Frenkel, we find an intervening hexatic phase near the critical point of the firstorder isostructural transition line. Very close to the critical point, a transition from the hexatic phase to a modulatedbondangle state is possible. Ising transitions in symmetrically confined twodimensional colloidal crystals with attractive wall potentials require a different model free energy, which we also discuss.
 Publication:

Physical Review E
 Pub Date:
 March 1996
 DOI:
 10.1103/PhysRevE.53.2560
 arXiv:
 arXiv:condmat/9510010
 Bibcode:
 1996PhRvE..53.2560C
 Keywords:

 82.70.Dd;
 68.35.Rh;
 61.72.Lk;
 64.70.Kb;
 Colloids;
 Phase transitions and critical phenomena;
 Linear defects: dislocations disclinations;
 Solidsolid transitions;
 Condensed Matter
 EPrint:
 12 pages, Latex file, 6 figures