title: Atomic-scale surface demixing in a eutectic liquid BiSn alloy.
abstract: Resonant x-ray reflectivity of the surface of the liquid phase of the Bi(43)Sn(57) eutectic alloy reveals atomic-scale demixing extending over three near-surface atomic layers. Because of the absence of an underlying atomic lattice which typically defines adsorption in crystalline alloys, studies of adsorption in liquid alloys provide unique insight on interatomic interactions at the surface. The observed composition modulation could be accounted for quantitatively by the Defay-Prigogine and Strohl-King multilayer extensions of the single-layer Gibbs model, revealing a near-surface domination of the attractive Bi-Sn interaction over the entropy.
authors.affiliation: Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA. oleg@xray.harvard.edu
authors.forename: Oleg G
authors.initials: OG
authors.lastname: Shpyrko
authors.forename: Alexei Yu
authors.initials: AY
authors.lastname: Grigoriev
authors.forename: Reinhard
authors.initials: R
authors.lastname: Streitel
authors.forename: Diego
authors.initials: D
authors.lastname: Pontoni
authors.forename: Peter S
authors.initials: PS
authors.lastname: Pershan
authors.forename: Moshe
authors.initials: M
authors.lastname: Deutsch
authors.forename: Ben
authors.initials: B
authors.lastname: Ocko
authors.forename: Mati
authors.initials: M
authors.lastname: Meron
authors.forename: Binhua
authors.initials: B
authors.lastname: Lin