title: Determination of size effects during the phase transition of a nanoscale Au-Si eutectic.
abstract: The phase diagram of a nanoscale system can be substantially different than in the bulk, but quantitative measurements have proven elusive. Here we use in situ microscopy to observe a phase transition in a nanoscale system, together with a simple quantitative model to extract the size effects from these measurements. We expose a Au particle to disilane gas, and observe the transition from a two-phase Au + AuSi system to single-phase AuSi. Size effects are evident in the nonlinear disappearance of the solid Au. Our analysis shows a substantial shift in the liquidus line, and a discontinuous change in the liquid composition at the transition. It also lets us estimate the liquid-solid interfacial free energy.
authors.affiliation: School of Materials Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: B J
authors.initials: BJ
authors.lastname: Kim
authors.forename: J
authors.initials: J
authors.lastname: Tersoff
authors.forename: C-Y
authors.initials: CY
authors.lastname: Wen
authors.forename: M C
authors.initials: MC
authors.lastname: Reuter
authors.forename: E A
authors.initials: EA
authors.lastname: Stach
authors.forename: F M
authors.initials: FM
authors.lastname: Ross