Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9818314 | Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms | 2005 | 7 Pages |
Abstract
Two complementary techniques, i.e. low-energy ion scattering in the neutral impact collision ion scattering spectroscopy (NICISS) mode and energy resolved He atom scattering (HAS) are combined to study the adatom formation mechanism on Ag(1 1 0). The NICISS spectra have been collected between 300 and 900 K along the ã0 0 1ã, ã11¯2ã and ã11¯0ã azimuthal directions while HAS measurements of the diffuse elastic peak has been performed along the ã11¯0ã directions between 190 and 800 K. Both techniques are sensitive to surface disorder and HAS data have been corrected by using the NICISS results in particular on the anharmonicity estimated through a two atoms scattering model. In fact, above 500 K surface anharmonicity is clearly detected and accompanies the proliferation of thermal induced defects. Without this anharmonic correction the adatom formation energy Ea is too low and similar to the surface diffusion barrier. Instead, including the anharmonicity the estimate, Ea = (0.38 ± 0.03) eV, is in excellent agreement with the predictions of molecular dynamics simulations.
Related Topics
Physical Sciences and Engineering
Materials Science
Surfaces, Coatings and Films
Authors
L. Pedemonte, G. Bracco,