title: Ageing of out-of-equilibrium nanoalloys by a kinetic mean-field approach.
abstract: This study describes the ageing of bimetallic nanoparticles using a kinetic mean-field method which provides the time evolution of the concentration for each site. We consider the cuboctahedron of 309 atoms in the Cu-Ag system, which is a prototype of systems with a strong tendency to phase separate. Starting from an initial homogenous configuration, we investigate the evolution towards the equilibrium configuration at different temperatures. Surprisingly, at low temperature, the kinetics exhibits a first transition towards an onion-like configuration followed by a second transition towards the equilibrium core-shell configuration. An analysis of the kinetics of the formation and then of the dissolution of the onion-like structure allows us to identify the main paths of the kinetic process.
authors.affiliation: CNRS, UMR 8182, F91405 Orsay Cedex, France.
authors.forename: F
authors.initials: F
authors.lastname: Berthier
authors.forename: A
authors.initials: A
authors.lastname: Tadjine
authors.forename: B
authors.initials: B
authors.lastname: Legrand