Size effects on melting and wetting in the Ga–Pb nano-alloy

Marco Allione (1) , Richard Kofman (1) , Franck Celestini (1) , Y. Lereah (2, 3)

1 LPMC - Laboratoire de physique de la matière condensée
2 Department of Physical Electronics
3 Wolfson Applied Materials Research Center

Ga-Pb alloys with 15 at% Pb mean concentration have been prepared at the nanoscale by means of evaporation-condensation technique in ultra high vacuum conditions. Transmission electron microscope images indicate that at room temperature, the system is a two-components breath figure composed of liquid Ga nanodrops containing Pb nanocrystals. Some thermodynamic properties of this nano-alloy are investigated for different temperatures and particle sizes. The results obtained put in evidence a large modification of the Ga-Pb bulk phase diagram: a decrease of the melting temperatures of the two components as well as the ones of the miscibility gap. Changes in the microscopic structure of the system as a function of temperature have been investigated and a full wetting transition from a dry to a completely wet state has been put in evidence.

Mots clés: Lead alloys; Gallium alloys; Binary alloys; Nanostructured materials; Microscopic structure; Transmission microscope; Nanocrystal; Temperature dependence; Phase diagrams; Particle size; Thermodynamic properties; Ambient temperature; Electron microscopes; Size effect

Domaines: Matière Molle [cond-mat.soft]; Science des matériaux [cond-mat.mtrl-sci]; Systèmes mésoscopiques et effet Hall quantique [cond-mat.mes-hall]

Marco Allione, Richard Kofman, Franck Celestini, Y. Lereah. Size effects on melting and wetting in the Ga–Pb nano-alloy. The European Physical Journal D : Atomic, molecular, optical and plasma physics, 2009, 52 (1-3), pp.207-210. ⟨10.1140/epjd/e2009-00072-2⟩. ⟨hal-00434457⟩