An unusual bimetallic p4g phase induced by Pd on Cu(001)

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

Detail(s)

Original languageEnglish
Pages (from-to)65-76
Journal / PublicationSurface Science
Volume359
Issue number1-3
Publication statusPublished - Jul 1996
Externally publishedYes

Abstract

The surface composition and structure of Pd on Cu(001) have been studied by a combination of low-energy ion scattering (LEIS) and low-energy electron diffraction (LEED). Palladium is incorporated into the surface at room temperature (≤50°C). This leads to the formation of two surface alloys: an ordered c(2 × 2) structure at 0.5 ML Pd, and a p4g structure at 1.0 ML Pd. The surface composition of the top two layers was determined by 1 keV Li+ ion scattering, using selective scattering geometries with calibration measurements on reference samples of Cu(001) and Pd(001). For the p4g structure, the results show a surface composition of 53at%Cu-47at% Pd in the first layer, while the second layer is 58at%Cu-42at%Pd. Several structural models that could be responsible for the p4g structure are proposed and investigated. The randomly mixed top Cu-Pd layer was found to be reconstructed such that the Pd (Cu) atoms are rotated by a lateral displacement of 0.25 ± 0.10 Å. The magnitude of this displacement was determined by measuring the azimuthal distributions of the Pd-Pd double scattering peak with 2 keV K+ ions. It is proposed, based on a hard-sphere model, that it is the moderate size mismatch between Cu and Pd atoms in the second c(2 × 2) mixed layer which drives the clockwise-anticlockwise rotation.

Research Area(s)

  • Alloys, Copper, Low energy electron diffraction (LEED), Low energy ion scattering (LEIS), Low index single crystal surfaces, Palladium, Surface structure, morphology, roughness and topography

Citation Format(s)

An unusual bimetallic p4g phase induced by Pd on Cu(001). / Yao, J.; Shen, Y. G.; O'Connor, D. J.; King, B. V.

In: Surface Science, Vol. 359, No. 1-3, 07.1996, p. 65-76.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review