Modeling the Anisotropy of Step Fluctuations on Surfaces: Theoretical Step Stiffness Confronts Experiment

نویسندگان

  • Timothy J. Stasevich
  • Theodore L. Einstein
  • Mikhail A. Anisimov
  • Jeff Prentis
چکیده

Title of dissertation: MODELING THE ANISOTROPY OF STEP FLUCTUATIONS ON SURFACES: THEORETICAL STEP STIFFNESS CONFRONTS EXPERIMENT Timothy J. Stasevich Doctor of Philosophy, 2006 Dissertation directed by: Professor Theodore L. Einstein Department of Physics In this thesis we study the anisotropy of step stiffness: an important parameter describing the fluctuations of surface steps within the continuum step model. Using a lattice-gas framework, we derive many practical formulas for the anisotropy of step stiffness on face centered cubic {001} and {111} surfaces. We compare our formulas to experiments on Ag an Cu surfaces and thereby predict the size of nearestneighbor, next-nearest-neighbor, and three-adatom, non-pairwise “trio” interactions between adatoms. To further corroborate our theory, we perform a series of firstprinciple calculations of the relevant adatom interactions. We also incorporate our formulas into simulations and model the relaxation of a Ag step initially pinned by surface impurities. Finally, we extend our theory to model Ag steps decorated by C60, from which we deduce the interaction energies between C60 and Ag, as well as between two C60 molecules. Together, our work provides a consistent picture of step stiffness anisotropy from an experimental, theoretical, and numerical perspective. MODELING THE ANISOTROPY OF STEP FLUCTUATIONS ON SURFACES: THEORETICAL STEP STIFFNESS CONFRONTS EXPERIMENT

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تاریخ انتشار 2006