Tight-binding Ising modeling of the interplay between bulk ordering and surface segregation in Pt-Ag nanoalloys
| Autor: | Guy Tréglia, Alexis Front, Fabienne Berthier, C. Mottet, Moncef Said, Abir Hizi |
|---|---|
| Přispěvatelé: | Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Université de Monastir - University of Monastir (UM), Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie du CNRS (INC)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Materials science
Chemical ordering Spinodal decomposition 02 engineering and technology 010402 general chemistry 01 natural sciences Monte Carlo simulations Truncated octahedron Tight binding Phase (matter) Materials Chemistry Cluster (physics) Tight-Binding Ising model Surface layer [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat] ComputingMilieux_MISCELLANEOUS Phase diagram [PHYS]Physics [physics] Condensed matter physics Alloys surfaces Surfaces and Interfaces Nanoalloys 021001 nanoscience & nanotechnology Condensed Matter Physics 0104 chemical sciences Surfaces Coatings and Films [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] Ising model 0210 nano-technology Surface segregation |
| Zdroj: | Surface Science Surface Science, Elsevier, 2020, 700, pp.121626. ⟨10.1016/j.susc.2020.121626⟩ Surface Science : A Journal Devoted to the Physics and Chemistry of Interfaces Surface Science : A Journal Devoted to the Physics and Chemistry of Interfaces, 2020, 700, pp.121626. ⟨10.1016/j.susc.2020.121626⟩ |
| ISSN: | 0039-6028 1879-2758 |
| DOI: | 10.1016/j.susc.2020.121626⟩ |
| Popis: | International audience; We use a Tight-Binding Ising Model (TBIM) with effective pair interactions depending on concentration able to reproduce the bulk phase diagram of Pt-Ag system and in particular its strong asymmetry as a function of composition. This system presents both an L1 1 ordered structure around equiconcentration and a wide miscibility gap on the Pt-rich side. Using Monte Carlo simulations in canonical and semi-grand canonical ensembles, we succeed in reproducing qualitatively the bulk phase diagram and we study the equilibrium configurations of the (111) and (100) surfaces, and truncated octahedron clusters. The infinite surfaces reproduce sensibly the bulk phase diagram except that they present a strong silver surface segregation limited to the top surface layer. The clusters behave differently due to the reduction of the miscibility gap when decreasing the cluster size and present two typical ordered phases related to the L1 1 phase: one characterized by pure concentric atomic layers starting from silver surface layer which extends up to the center of the cluster, and the other one at higher silver concentration where the L1 1 phase is perfectly oriented along one (111) direction of the cluster. The later one has already been reported by recent experiments [1]. |
| Databáze: | OpenAIRE |
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