Delfour L, Creuze J, Legrand B. Exotic behavior of the outer shell of bimetallic nanoalloys.
PHYSICAL REVIEW LETTERS 2009;
103:205701. [PMID:
20365993 DOI:
10.1103/physrevlett.103.205701]
[Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Revised: 10/02/2009] [Indexed: 05/29/2023]
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.
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