Campus Units

Mathematics, Physics and Astronomy, Chemistry, Materials Science and Engineering, Ames Laboratory

Document Type

Article

Publication Version

Published Version

Publication Date

2013

Journal or Book Title

Physical Review B

Volume

88

Issue

15

First Page

155434-1

Last Page

155434-10

DOI

10.1103/PhysRevB.88.155434

Abstract

Submonolayer homoepitaxial fcc (110) systems display behavior reflecting strong anisotropy at lower temperatures, including one-dimensional decay during Ostwald ripening of rectangular islands maintaining constant width in the 〈001〉 direction. To appropriately describe this behavior, we first develop a refined continuum Burton-Cabrera-Frank formalism, which accounts for a lack of equilibration of island shape and importantly also for inhibited incorporation of adatoms at almost-faceted 〈1̄10〉 island edges through effective kinetic coefficients. This formalism is shown to describe accurately the adatom diffusion fluxes between islands and thus island evolution for a complex experimental island configuration, as confirmed by matching results from realistic atomistic simulations for this configuration. This approach also elucidates basic dependencies of flux on island geometry and temperature. Second, a further refinement is presented incorporating separate terrace and edge adatom density fields either in a continuum setting or alternatively in a spatially discrete diffusion equation setting. The second approach allows more flexibility and accuracy in accounting for edge-diffusion kinetics including corner rounding, a lack of equilibration of the edge adatom density atisland edges, and the effect of rare kinks onisland edges. Significantly, it suggests facile two-way corner rounding at the island periphery during island decay, contrasting the previous picture.

Comments

This article is from Physical Review B 88 (2013): 155434, doi: 10.1103/PhysRevB.88.155434, Posted with permission.

Copyright Owner

American Physical Society

Language

en

File Format

application/pdf

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