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Title: Communication: Diverse nanoscale cluster dynamics: Diffusion of 2D epitaxial clusters

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, D N ~ 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 N p = L 2 and L(L+1) for integer L = 3,4,… (with unique square or near-square ground state shapes), and also for N p+3, N p+4,…. In contrast, fast facile nucleation-free diffusion displaying strong size scaling β ≈ 2.5 occurs for sizes N p+1 and N p+2. D N versus N oscillates strongly between the slowest branch (for N p+3) and the fastest branch (for N p+1). All branches merge for N = O(10 2), but macroscale behavior is only achieved for much larger N = O(10 3). Here, this analysis reveals the unprecedented diversity of behavior on the nanoscale.
Authors:
 [1] ; ORCiD logo [1] ; ORCiD logo [1]
  1. Ames Lab. and Iowa State Univ., Ames, IA (United States)
Publication Date:
Report Number(s):
IS-J-9460
Journal ID: ISSN 0021-9606; TRN: US1800287
Grant/Contract Number:
CHE-1507223; AC02-07CH11358
Type:
Accepted Manuscript
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 147; Journal Issue: 20; Journal ID: ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1411951
Alternate Identifier(s):
OSTI ID: 1410400

Lai, King C., Evans, James W., and Liu, Da -Jiang. Communication: Diverse nanoscale cluster dynamics: Diffusion of 2D epitaxial clusters. United States: N. p., Web. doi:10.1063/1.5008424.
Lai, King C., Evans, James W., & Liu, Da -Jiang. Communication: Diverse nanoscale cluster dynamics: Diffusion of 2D epitaxial clusters. United States. doi:10.1063/1.5008424.
Lai, King C., Evans, James W., and Liu, Da -Jiang. 2017. "Communication: Diverse nanoscale cluster dynamics: Diffusion of 2D epitaxial clusters". United States. doi:10.1063/1.5008424.
@article{osti_1411951,
title = {Communication: Diverse nanoscale cluster dynamics: Diffusion of 2D epitaxial clusters},
author = {Lai, King C. and Evans, James W. and Liu, Da -Jiang},
abstractNote = {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). Here, this analysis reveals the unprecedented diversity of behavior on the nanoscale.},
doi = {10.1063/1.5008424},
journal = {Journal of Chemical Physics},
number = 20,
volume = 147,
place = {United States},
year = {2017},
month = {11}
}