title: Atomic diffusion within individual gold nanocrystal.
abstract: Due to their excess surface free energy and structural instabilities, nanoparticles exhibit interesting physical and chemical properties. There has been an ever-growing interest in investigating these properties, driven by the desire to further miniaturize electronic devices, develop new functional materials and catalysts. Here, the intriguing question of how diffusion evolves in a single nanoparticle is investigated by measuring the spatial and temporal variations of the diffracted coherent X-ray intensity during copper diffusion into a gold nanocrystal. Dislocation loops formed from the insertion of single layer of extra atoms between neighbouring gold host lattice planes are detected. Au-Cu alloy channels are found to penetrate the nanocrystal due to the differential diffusion rate along different directions. With the advent of higher brilliance sources and free-electron-lasers, Bragg Coherent X-ray Diffraction Imaging can play an important role in unveiling atomic behaviours in three dimensions for nanomaterials during various fundamental processes.
authors.affiliation: London Centre for Nanotechnology, University College London, London WC1H 0AH, UK.
authors.forename: Gang
authors.initials: G
authors.lastname: Xiong
authors.affiliation: London Centre for Nanotechnology, University College London, London WC1H 0AH, UK.
authors.forename: Jesse N
authors.initials: JN
authors.lastname: Clark
authors.affiliation: Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, UK.
authors.forename: Chris
authors.initials: C
authors.lastname: Nicklin
authors.affiliation: Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, UK.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Rawle
authors.affiliation: 1] London Centre for Nanotechnology, University College London, London WC1H 0AH, UK [2] Research Complex at Harwell, Harwell Oxford, Didcot, OX11 0FA, UK.
authors.forename: Ian K
authors.initials: IK
authors.lastname: Robinson