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Communication: Diverse nanoscale cluster dynamics: Diffusion of 2D epitaxial clusters
Ames Laboratory Accepted Manuscripts
  • King C. Lai, Iowa State University and Ames Laboratory
  • James W. Evans, Iowa State University and Ames Laboratory
  • Da-Jiang Liu, Ames Laboratory
Publication Date
Ames Laboratory; Physics and Astronomy
Report Number
IS-J 9460
Journal Title
Journal of Chemical Physics
The dynamics of nanoscale clusters can be distinct from macroscale behavior described by continuum formalisms. For diffusion of 2D clusters of N atoms in homoepitaxial systems mediated by edge atom hopping, macroscale theory predicts simple monotonic size scaling of the diffusion coefficient, DN ∼ N−β, with β = 3/2. However, modeling for nanoclusters on metal(100) surfaces reveals that slow nucleation-mediated diffusion displaying weak size scaling β < 1 occurs for “perfect” sizes Np = L2 and L(L+1) for integer L = 3,4,… (with unique square or near-square ground state shapes), and also for Np+3, Np+4,…. In contrast, fast facile nucleation-free diffusion displaying strong size scaling β ≈ 2.5 occurs for sizes Np+1 and Np+2. DN versus N oscillates strongly between the slowest branch (for Np+3) and the fastest branch (for Np+1). All branches merge for N = O(102), but macroscale behavior is only achieved for much larger N = O(103). This analysis reveals the unprecedented diversity of behavior on the nanoscale.
Iowa State University Digital Repository, Ames IA (United States)
Citation Information
King C. Lai, James W. Evans and Da-Jiang Liu. "Communication: Diverse nanoscale cluster dynamics: Diffusion of 2D epitaxial clusters" Vol. 147 Iss. 20 (2017) p. 201101
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