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Title: Facet-controlled phase separation in supersaturated Au-Ni nanoparticles upon shape equilibration

Solid-state dewetting is used to fabricate supersaturated, submicron-sized Au-Ni solid solution particles out of thin Au/Ni bilayers by means of a rapid thermal annealing technique. Phase separation in such particles is studied with respect to their equilibrium crystal (or Wulff) shape by subsequent annealing at elevated temperature. It is found that (100) faceting planes of the equilibrated particles are enriched with Ni and (111) faces with Au. Both phases are considered by quantum-mechanical calculations in combination with an error-reduction scheme that was developed to compensate for a missing exchange-correlation potential that would reliably describe both Au and Ni. The observed phase configuration is then related to the minimization of strongly anisotropic elastic energies of Au- and Ni-rich phases and results in a rather unique nanoparticle composite state that is characterized by nearly uniform value of elastic response to epitaxial strains all over the faceted surface. The same conclusion is yielded also by evaluating bi-axial elastic moduli when employing interpolated experimental elastic constants. This work demonstrates a useful route for studying features of physical metallurgy at the mesoscale.
Authors:
; ; ; ; ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [3] ;  [3] ;  [2]
  1. Department of Materials for Electronics and Electrical Engineering, Institute of Materials Science and Engineering and Institute of Micro- and Nanotechnologies MacroNano, TU Ilmenau, D-98693 Ilmenau (Germany)
  2. Institute of Physics of Materials, Academy of Sciences of the Czech Republic, v.v.i., Žižkova 22, CZ-616 62 Brno (Czech Republic)
  3. (Czech Republic)
  4. Department of Physical Metallurgy and Materials Testing, Montanuniversität Leoben, A-8700 Leoben (Austria)
  5. Central European Institute of Technology, CEITEC MU, Masaryk University, Kamenice 5, CZ-625 00 Brno (Czech Republic)
Publication Date:
OSTI Identifier:
22489127
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 7; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANISOTROPY; ANNEALING; CORRELATIONS; EPITAXY; NANOPARTICLES; PHYSICAL METALLURGY; QUANTUM MECHANICS; SOLID SOLUTIONS; SURFACES