Double-segregation effect in AgxPd1-x/Ru(0001) thin film nanostructures
2008 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 77, no 12Article in journal (Refereed) Published
We study the structural properties of ultrathin AgxPd1-x films on top of a Ru(0001) substrate. Effective interatomic interactions, obtained from first-principles calculations, have been used in Monte Carlo simulations to derive the distribution of the alloy components in a four-monolayer (4-ML) Ag-Pd film. Though Ag-Pd alloys show complete solubility in the bulk, the thin film geometry leads to a pronounced segregation between Ag and Pd atoms with a strong preference of Ag atoms toward the surface and Pd atoms toward the interface. The theoretical prediction of this double-segregation effect is strongly supported by photoelectron spectroscopy experiments carried out for 4-ML thin films. We also show, in an additional experiment, that even in the case where initially 1 ML Ag is buried under 6 ML Pd, the whole Ag ML segregates to the surface.
Place, publisher, year, edition, pages
2008. Vol. 77, no 12
coherent-potential approximation, transition-metal alloys, surface, segregation, cu-ni, 1st-principles, energy, model, pd, stability, ru(0001)
IdentifiersURN: urn:nbn:se:kth:diva-17425DOI: 10.1103/PhysRevB.77.125406ISI: 000254543000123ScopusID: 2-s2.0-41449117478OAI: oai:DiVA.org:kth-17425DiVA: diva2:335469
QC 201005252010-08-052010-08-05Bibliographically approved