Microscopic Structure of the Wetting Film at the Surface of Liquid Ga-Bi Alloys

H. Tostmann; E. DiMasi; O. G. Shpyrko; P. S. Pershan; B. M. Ocko; M. Deutsch

doi:10.1103/PhysRevLett.84.4385

Microscopic Structure of the Wetting Film at the Surface of Liquid Ga-Bi Alloys

H. Tostmann, E. DiMasi, O. G. Shpyrko, P. S. Pershan, B. M. Ocko, and M. Deutsch

Phys. Rev. Lett. 84, 4385 – Published 8 May 2000

Abstract

X-ray reflectivity measurements of the binary liquid Ga-Bi alloy reveal a dramatically different surface structure above and below the monotectic temperature $T_{mono} = 222 ° C$ . A Gibbs-adsorbed Bi monolayer resides at the surface in both regimes. However, a $30 Å$ thick, Bi-rich wetting film intrudes between the Bi monolayer and the Ga-rich bulk for $T > T_{mono}$ . The wetting film's internal structure, not hitherto measured, is determined with $Å$ resolution, showing a concentration gradient not predicted by theory and a highly diffuse interface with the bulk phase.

Received 12 July 1999

DOI:https://doi.org/10.1103/PhysRevLett.84.4385

Authors & Affiliations

H. Tostmann¹, E. DiMasi², O. G. Shpyrko¹, P. S. Pershan¹, B. M. Ocko², and M. Deutsch³

¹Division of Applied Sciences and Department of Physics, Harvard University, Cambridge, Massachusetts 02138
²Department of Physics, Brookhaven National Laboratory, Upton, New York 11973-5000
³Department of Physics, Bar-Ilan University, Ramat-Gan 52100, Israel