Europhys. Lett.
Volume 74, Number 2, April 2006
Page(s) 355 - 361
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 15 March 2006
Europhys. Lett., 74 (2), pp. 355-361 (2006)
DOI: 10.1209/epl/i2005-10532-1

Solid-liquid transition in 2D dipolar systems

A. Ghazali1 and J.-C. S. Lévy2

1  Institut des NanoSciences de Paris, UMR 7588-CNRS, Universités Paris 6 & Paris 7 Campus Boucicaut, 75015 Paris, France
2  Laboratoire MPQ UMR 7162-CNRS, Université Paris 7, case 7020 2 place Jussieu, 75251 Paris, France

received 17 November 2005; accepted in final form 23 February 2006
published online 15 March 2006

The solid-liquid phase diagram of two-dimensional, laterally confined systems made of interacting parallel dipoles normal to the plane is investigated by Monte Carlo method. The lowest-energy solid phase is relaxed from a regular triangular lattice. This Wigner crystal phase keeps the main features of the original monocrystal. On the other hand, the solid phase relaxed from a random initial configuration has a slightly higher energy and is called Wigner glass. It exhibits randomly oriented crystallites separated by chains of topological defects, namely alternate 5- and 7-nearest-neighbour sites. These chains start to move within the solid phase at a temperature lower than the bulk melting temperature.

75.70.Rf - Surface magnetism.
64.70.Dv - Solid-liquid transitions.
62.20.Dc - Elasticity, elastic constants.

© EDP Sciences 2006