title: Heterogeneous nucleation and shape transformation of multicomponent metallic nanostructures.
abstract: To be able to control the functions of engineered multicomponent nanomaterials, a detailed understanding of heterogeneous nucleation at the nanoscale is essential. Here, by using in situ synchrotron X-ray scattering, we show that in the heterogeneous nucleation and growth of Au on Pt or Pt-alloy seeds the heteroepitaxial growth of the Au shell exerts high stress (∼2 GPa) on the seed by forming a core/shell structure in the early stage of the reaction. The development of lattice strain and subsequent strain relaxation, which we show using atomic-resolution transmission electron microscopy to occur through the slip of {111} layers, induces morphological changes from a core/shell to a dumbbell structure, and governs the nucleation and growth kinetics. We also propose a thermodynamic model for the nucleation and growth of dumbbell metallic heteronanostructures.
authors.affiliation: Nanoscience and Technology Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA.
authors.forename: Soon Gu
authors.initials: SG
authors.lastname: Kwon
authors.affiliation: Nanoscience and Technology Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA.
authors.forename: Galyna
authors.initials: G
authors.lastname: Krylova
authors.affiliation: Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, USA.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Phillips
authors.affiliation: Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, USA.
authors.forename: Robert F
authors.initials: RF
authors.lastname: Klie
authors.affiliation: 1] CSRRI-IIT, MRCAT, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA [2] Physics Department, Advanced Materials Group, Illinois Institute of Technology, Chicago, Illinois 60616, USA.
authors.forename: Soma
authors.initials: S
authors.lastname: Chattopadhyay
authors.affiliation: 1] CSRRI-IIT, MRCAT, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA [2] Physics Department, Advanced Materials Group, Illinois Institute of Technology, Chicago, Illinois 60616, USA.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Shibata
authors.affiliation: Chemical Science and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA.
authors.forename: Emilio E
authors.initials: EE
authors.lastname: Bunel
authors.affiliation: Nanoscience and Technology Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA.
authors.forename: Yuzi
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Center for Advanced Radiation Sources, University of Chicago, Argonne, Illinois 60439, USA.
authors.forename: Vitali B
authors.initials: VB
authors.lastname: Prakapenka
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA.
authors.forename: Byeongdu
authors.initials: B
authors.lastname: Lee
authors.affiliation: Nanoscience and Technology Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA.
authors.forename: Elena V
authors.initials: EV
authors.lastname: Shevchenko