title: Energetic, electronic, and thermal effects on structural properties of Ag-Au nanoalloys.
abstract: Using a genetic algorithm global optimization approach combined with density functional theory calculations, a search has been made for the lowest energies of (AgAu)(m) nanoalloys with 20-150 atoms (diameters of 1.0-2.0 nm). A total of 31 decahedra, 35 icosahedra, and 2 close-packed motifs are identified in two icosahedral windows and one Marks-decahedral window. These structural motifs have twinned, capped, defective, and distorted atomic packing compared to classical clusters, such as the icosahedron. The magic numbers, atomic ordering, electronic structure, and melting behavior are further studied, and a new poly-nanocrystalline decahedral motif, Ag(44)Au(44), is found to have high structural, electronic, and thermal stability. Our results show that alloying can lead to a remarkable stabilization of local order and provide a comprehensive model for the structures and properties of Ag-Au nanoalloys.
authors.affiliation: School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
authors.forename: Fuyi
authors.initials: F
authors.lastname: Chen
authors.forename: Roy L
authors.initials: RL
authors.lastname: Johnston
mesh_terms: D000497:Alloys / Q000737:chemistry*; D004583:Electrons; D019277:Entropy; D006046:Gold / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry*; D044367:Phase Transition; D011789:Quantum Theory; D012834:Silver / Q000737:chemistry*; D013696:Temperature
chemical_list: D000497:Alloys; D012834:Silver; D006046:Gold