Europhys. Lett.
Volume 74, Number 6, June 2006
Page(s) 1046 - 1052
Section Condensed matter: structural, mechanical and thermal properties
Published online 12 May 2006
Europhys. Lett., 74 (6), pp. 1046-1052 (2006)
DOI: 10.1209/epl/i2006-10044-6

Induced order and re-entrant melting in classical two-dimensional binary clusters

K. Nelissen1, B. Partoens1, I. Schweigert1, 2 and F. M. Peeters1

1  Departement Fysica, Universiteit Antwerpen Groenenborgerlaan 171, B-2020 Antwerpen, Belgium
2  Institute of Theoretical and Applied Mechanics Institutskaya 4/1, Novosibirsk 630090, Russia

received 12 January 2006; accepted in final form 13 April 2006
published online 12 May 2006

A binary system of classical charged particles interacting through a dipole repulsive potential and confined in a two-dimensional hard-wall trap is studied by Brownian dynamics simulations. We found that the presence of small particles stabilizes the angular order of the system as a consequence of radial fluctuations of the small particles. There is an optimum in the increased rigidity of the cluster as function of the number of small particles. The small (i.e. defect) particles melt at a lower temperature compared to the big particles and exhibit a re-entrant behavior in its radial order that is induced by the intershell rotation of the big particles.

64.60.Cn - Order-disorder transformations; statistical mechanics of model systems.
83.10.Mj - Molecular dynamics, Brownian dynamics.
83.10.Rs - Computer simulation of molecular and particle dynamics.

© EDP Sciences 2006