title: 3D Imaging of Twin Domain Defects in Gold Nanoparticles.
abstract: Topological defects are ubiquitous in physics and include crystallographic imperfections such as defects in condensed matter systems. Defects can determine many of the material's properties, thus providing novel opportunities for defect engineering. However, it is difficult to track buried defects and their interfaces in three dimensions with nanoscale resolution. Here, we report three-dimensional visualization of gold nanocrystal twin domains using Bragg coherent X-ray diffractive imaging in an aqueous environment. We capture the size and location of twin domains, which appear as voids in the Bragg electron density, in addition to a component of the strain field. Twin domains can interrupt the stacking order of the parent crystal, leading to a phase offset between the separated parent crystal pieces. We utilize this phase offset to estimate the roughness of the twin boundary. We measure the diffraction signal from the crystal twin and show its Bragg electron density fits into the parent crystal void. Defect imaging will likely facilitate improvement and rational design of nanostructured materials.
authors.affiliation: †Department of Physics, University of California-San Diego, La Jolla, California 92093-0319, United States.
authors.forename: Andrew
authors.initials: A
authors.lastname: Ulvestad
authors.affiliation: ‡Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States.|§Center for Free-Electron Laser Science (CFEL), Deutsches Elektronensynchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany.
authors.forename: Jesse N
authors.initials: JN
authors.lastname: Clark
authors.affiliation: ∥Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States.
authors.forename: Ross
authors.initials: R
authors.lastname: Harder
authors.affiliation: ⊥London Center for Nanotechnology, University College London, London WC1E 6BT, United Kingdom.|∇Research Complex at Harwell, Didcot, Oxfordshire OX11 0DE, United Kingdom.
authors.forename: Ian K
authors.initials: IK
authors.lastname: Robinson
authors.affiliation: †Department of Physics, University of California-San Diego, La Jolla, California 92093-0319, United States.
authors.forename: Oleg G
authors.initials: OG
authors.lastname: Shpyrko
mesh_terms: D006046:Gold / Q000737:chemistry*; D021621:Imaging, Three-Dimensional; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D014961:X-Ray Diffraction
chemical_list: D006046:Gold
keywords: X-ray imaging; coherent imaging; defects; gold nanoparticle; twin domain