Island shape controls magic-size effect for heteroepitaxial diffusion

Wu, HH (Wu, Henry H.); Signor, AW (Signor, A. W.); Trinkle, DR (Trinkle, Dallas R.)

JOURNAL OF APPLIED PHYSICS, 108 (2): Art. No. 023521 JUL 15 2010

DOI: 10.1063/1.3455848

Lattice mismatch of Cu on Ag(111) produces fast diffusion for "magic sizes" of islands. A size- and shape-dependent reptation mechanism is responsible for low diffusion barriers. Initiating the reptation mechanism requires a suitable island shape, not just magic sizes. Shape determines the dominant diffusion mechanism and leads to multiple clearly identifiable magic-size trends for diffusion depending on the number of atoms whose bonds are shortened during diffusion, which ultimately affects the self-assembly of islands. (C) 2010 American Institute of Physics. doi : 10.1063/1.3455848

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