Abstract
By means of first principles simulations we demonstrate that tiny deviations from stoichiometry in the bulk composition of the ordered alloy have a great impact on the atomic configuration of the (111) surface. We predict that at the (111) surface of the and alloys corresponds to the (111) truncation of the bulk ordered structure. However, the (111) surface of the nickel deficient alloy is strongly enriched by Pt and should exhibit the pattern of the structure. Such a drastic change in the segregation behavior is due to the presence of different antisite defects in the Ni- and Pt-rich alloys and is a manifestation of the so-called off-stoichiometric effect.
- Received 6 March 2002
DOI:https://doi.org/10.1103/PhysRevLett.90.026105
©2003 American Physical Society