Title

Diffusion barriers for Ag and Cu adatoms on the terraces and step edges on Cu(100) and Ag(100): An ab initio study

Authors

Authors

H. Yildirim;T. S. Rahman

Abbreviated Journal Title

Phys. Rev. B

Keywords

ab initio calculations; adsorbed layers; copper; density functional; theory; diffusion barriers; silver; SURFACE SELF-DIFFUSION; GENERALIZED GRADIENT APPROXIMATION; ENERGY; ELECTRON-DIFFRACTION; MOLECULAR-BEAM EPITAXY; WAVE BASIS-SET; FCC(100); SURFACES; ATOMIC VIEW; HOMOEPITAXIAL GROWTH; MASS-TRANSPORT; CRYSTAL-GROWTH; Physics, Condensed Matter

Abstract

We present the results of density-functional-theory-based calculations for the activation energies for the diffusion of adatoms (Cu or Ag) on Cu(100) and Ag(100) with and without steps. We find that only for Cu on Ag(100), exchange is the dominant mechanism for the diffusion on terraces. On the other hand, for diffusion at step edges, exchange is the dominant mechanism except for Ag on Cu(100). This result also indicates that incorporation of Cu atoms into the step edges of Ag(100) costs only 330 meV, while the energy cost for Ag incorporation into Cu(100) step edge is much higher (about 700 meV). We find the hierarchy of Ehrlich-Schwoebel barriers to be: 170 meV for Ag on Cu(100); 60 meV for Cu on Cu(100); 20 meV for Ag on Ag(100), and -30 meV (-270 meV) for Cu on Ag(100). These barriers point to a striking difference in the growth modes for Ag layers on Cu(100) and Cu layers on Ag(100).

Journal Title

Physical Review B

Volume

80

Issue/Number

23

Publication Date

1-1-2009

Document Type

Article

Language

English

First Page

9

WOS Identifier

WOS:000273228800109

ISSN

1098-0121

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