Surface Freezing in Binary Liquid Gold-Silicon Alloy

ORAL

Abstract

We present experimental x-ray studies of formation of a 2D solid monolayer at the liquid-vapor interface of AuSi eutectic alloy above bulk melting point $T_{melt}=363^{\circ}$C. Additionally, at temperature $T=T_{melt}+12^{\circ}C$ the 2D surface-frozen layer undergoes a solid-solid surface phase transition. Surface-induced atomic layering structure normal to the surface was found to be significantly enhanced for low-temperature 2D phase (layering length $\approx$ 3~nm), while reverting to classical layering length of $\approx$ 1~nm above surface transition temperature. The Gold-Silicon eutectic is the first miscible binary metallic system for which such surface freezing behavior has been observed.

*Synchrotron measurements performed at ChemMatCARS, Advanced Photon Source, Argonne National Lab and supported by DOE grants DE-FG02-88-ER45379 and DE-AC02-98CH10886.

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Authors

  • Oleg Shpyrko

  • Alexei Grigoriev

  • Reinhard Streitel

  • Peter Pershan

    • Harvard University
    • Physics Department and DEAS, Harvard University, Cambridge, MA 02138

  • Ben Ocko

    • Brookhaven National Laboratory, Upton, NY 11973

  • Moshe Deutsch

    • Bar-Ilan University, Ramat-Gan 52900, Israel