Hostname: page-component-7b9c58cd5d-bslzr Total loading time: 0.001 Render date: 2025-03-14T11:38:57.903Z Has data issue: false hasContentIssue false
  • English
  • Français

Island Size and Environment Dependence of Adatom Capture: Cu/Co Islands on Ru(0001)

Published online by Cambridge University Press:  10 February 2011

M.C. Bartelt ,
J.W. Evans ,
A.K. Schmid  and
R.Q. Hwang
M.C. Bartelt
Affiliation:
Sandia National Laboratories, Livermore, CA 94550
J.W. Evans
Affiliation:
Iowa State University, Department of Mathematics and Ames Laboratory, Ames, IA 50011
A.K. Schmid
Affiliation:
Sandia National Laboratories, Livermore, CA 94550
R.Q. Hwang
Affiliation:
Sandia National Laboratories, Livermore, CA 94550
Get access

Abstract

The rate of capture by stable Co islands on Ru(0001) of additionally deposited Cu atoms is quantified using scanning tunneling microscopy, kinetic Monte Carlo simulations, and diffusion equation analyses. We find strong dependence of the capture rates on Co-island size, larger islands showing larger capture rates, qualitatively distinct from self-consistent mean-field predictions. The observed size dependence is shown to reflect larger island-free areas surrounding bigger islands, i.e., a strong correlation between island sizes and separations neglected in mean-field treatments.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 528: Symposia AA – Mechanisms & Principals of Epitaxial Growth in Metallic Systems , 1998 , 253
Copyright
Copyright © Materials Research Society 1998

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Hwang, R.Q. and Bartelt, M.C., Chem. Rev. 97, 1063 (1997); G. Rosenfeld, B. Poelsema and G. Comsa, in The Chemical Physics of Solid Surfaces, edited by D.A. King and D.P. Woodruff, Vol.8 (Elsevier Science, 1997); B. MUller, L. Nedelmann, B. Fischer, H. Brune, and K. Kern, in Surface Diffusion: Atomistic and Collective Processes, edited by M.C. Tringides, NATO ASI Series, Vol.360 (Plenum Press, 1997).Google Scholar
2. Bartelt, M.C. and Evans, J.W., Phys. Rev. B 54, R17359 (1996); J.W. Evans and M.C. Bartelt, in Morphological Organization During Epitaxial Growth and Removal, edited by Z. Zhang and M.G. Lagally (World Scientific, 1998).Google Scholar
3. Venables, J.A. and Ball, D.J., Proc. R. Soc. London, Ser. A 322, 331 (1971); J.A. Venables, Philos. Mag. 27, 697 (1973); S. Stoyanov and D. Kashchiev, Curr. Topics in Mater. Sci. 7, 69 (1981); G.S. Bales and D.C. Chrzan, Phys. Rev. B 50, 6057 (1994), report a self-consistent analysis which obtains σ/σav∼(S/Sav)1/2for circular islands of large size s, contrasting the quasi-linear s-dependence observed in simulations and experiment.Google Scholar
4. Bartelt, M.C., Schmid, A.K., Evans, J.W., and Hwang, R.Q., submitted (1998).Google Scholar
5. Günther, C., Günther, S., Kopatzki, E., Hwang, R.Q., Shroder, J., Vrijmoeth, J., and Behm, R.J., Ber. Buns. Phys. Chem. 97, 522 (1993).Google Scholar
6. At RT, we measured Nav≍840/μm2, with similar flux. If island formation is irreversible, simulations [2] obtain h=109/s for the effective hop rate of Co adatoms on Ru(0001) at RT. At 50°C, simulations then predict Nav≍620/Iμm2, much larger than the observed 130/μm2, so presumably island formation is not irreversible, or islands are mobile, at 50°C.Google Scholar
7. Bartelt, M.C., Schmid, A.K., Evans, J.W., and Hwang, R.Q., in preparation.Google Scholar
8. Schmid, A.K., Hamilton, J.C., Bartelt, N.C., and Hwang, R.Q., Phys. Rev. Lett. 77, 2977 (1996).Google Scholar
9. Increasing the coverage from θ to θ+δθ, increases the size of an island of size s by the average amount , using N1≍F/(hσavNav). So, Ms=(σs/σav)(δθ/Nav), if σ/σav and Nav are weakly dependent on θ in the interval δθ.Google Scholar
10. A Voronoi tesselation is constructed by drawing the perpendicular bisecting lines to the lines joining the center-of-mass of each island to those of its nearest-neighbor islands. Each convex polygonal region defined by the intersection of these lines is a Voronoi cell. See, for example, Preparata, F.P., Shamos, M.I., and Preparata, R. Shamos, Computational Geometry: An Introduction (Springer-Verlag, 1985).Google Scholar
11. Stoyanov, S., Curr. Top. Mater. Sci. 3, 421 (1979); P.A. Mulheran and J.A. Blackman, Philos. Mag. Lett. 72, 55 (1995); Phys. Rev. B 53, 10261 (1996).Google Scholar
12. Evans, J.W., Phys. Rev. A 40, 2868 (1989).Google Scholar