title: Local symmetries and order-disorder transitions in small macroscopic Wigner islands.
abstract: The influence of local order on the disordering scenario of small Wigner islands is discussed. A first disordering step is put in evidence by the time correlation functions and is linked to individual excitations resulting in configuration transitions, which are very sensitive to the local symmetries. This is followed by two other transitions, corresponding to orthoradial and radial diffusion, for which both individual and collective excitations play a significant role. Finally, we show that, contrary to large systems, the focus that is commonly made on collective excitations for such small systems through the Lindemann criterion has to be made carefully in order to clearly identify the relative contributions in the whole disordering process.
authors.affiliation: Laboratoire Matière et Systèmes Complexes, Université Paris 7, Unité mixte du CNRS 7057, 140 rue de Lourmel, 75015 Paris, France.
authors.forename: Gwennou
authors.initials: G
authors.lastname: Coupier
authors.forename: Claudine
authors.initials: C
authors.lastname: Guthmann
authors.forename: Yves
authors.initials: Y
authors.lastname: Noat
authors.forename: Michel Saint
authors.initials: MS
authors.lastname: Jean