Grazing incidence X-ray scattering reveals that liquid AuSi alloy shows solid-like crystal structure at surface

Professor P. Pershan (Harvard University, USA) and his colleagues recently found a crystalline monolayer at the surface of the eutectic liquid Au₈₂Si₁₈, at temperatures above the alloy's melting point. This is unusual for a liquid surface, as the atomic arrangements are ordinarily strongly disordered. In addition, they found that the gold-silicon eutectic alloy has 7-8 layers near its surface, whereas many metallic liquids typically show only 2-3 distinct atomic layers. The phenomena are considered as indicative of surface freezing. The research group employed X-ray reflectivity and grazing incidence X-ray diffraction techniques for the analysis. For more information, see the paper, "Surface Crystallization in a Liquid AuSi Alloy", Oleg G. Shpyrko et al., Science 313, 77 (2006).