title: Exotic behavior of the outer shell of bimetallic nanoalloys.
abstract: In order to build the phase diagram of Cu-Ag nanoalloys, segregation isotherms for the different sites of the outer shell of a 405-atom cluster have been obtained by means of Monte Carlo simulations using N-body interatomic potentials. A dynamical equilibrium in phase space is observed for the (001) facets as well as for the (111) facets of the truncated octahedron. For the (001) facets, the bistability originates from a structural transition, the facets oscillating collectively between a Cu-rich square shape of coordinence 4 and an Ag-rich diamond shape of coordinence 6. For the (111) facets, the bistability is purely chemical and affects each facet individually. We thus predict the possible coexistence of Cu-pure and Ag-pure (111) facets within the same nanoparticle.
authors.affiliation: SRMP-DMN, CEA Saclay, F91191 Gif-sur-Yvette Cedex, France.
authors.forename: L
authors.initials: L
authors.lastname: Delfour
authors.forename: J
authors.initials: J
authors.lastname: Creuze
authors.forename: B
authors.initials: B
authors.lastname: Legrand