Low energy slowing down of nanosize copper clusters on gold (111) surfaces

The slowing down of copper clusters formed by 440 atoms on a gold (1 1 1) s urface is studied in detail by means of molecular dynamics. The atomic clas sical molecular dynamics is based on the second moment approximation of the tight binding model and, in addition, accounts for the electron-phonon cou pling in the frame of the Sommerfeld theory of metals. The slowing down ene rgy range is 0-1 eV/atom, which is characteristic of low energy cluster bea m deposition (LECBD). A pronounced epitaxy of the copper clusters is found. However, their morphology is significantly energy dependent. The structure and the radial pair correlation functions are used to study the details of the epitaxial properties as well as the pronounced relaxation in the inter facial cluster atom positions due to the lattice mismatch between copper an d gold. The effect of the cluster and substrate average temperature is inve stigated and can be distinguished from the kinetic effect of the cluster im pact. (C) 2000 Elsevier Science B.V. All rights reserved.