title: Direct observation of depth-dependent atomic displacements associated with dislocations in gallium nitride.
abstract: We demonstrate that the aberration-corrected scanning transmission electron microscope has a sufficiently small depth of field to observe depth-dependent atomic displacements in a crystal. The depth-dependent displacements associated with the Eshelby twist of dislocations in GaN normal to the foil with a screw component of the Burgers vector are directly imaged. We show that these displacements are observed as a rotation of the lattice between images taken in a focal series. From the sense of the rotation, the sign of the screw component can be determined.
authors.affiliation: Department of Materials, University of Oxford, OX1 3PH Oxford, United Kingdom.
authors.forename: J G
authors.initials: JG
authors.lastname: Lozano
authors.affiliation: Department of Materials, University of Oxford, OX1 3PH Oxford, United Kingdom.
authors.forename: H
authors.initials: H
authors.lastname: Yang
authors.affiliation: Departamento de Ingeniería Informática, CASEM, Universidad de Cadiz, Polígono Rio San Pedro s/n, 11510 Puerto Real (Cadiz), Spain.
authors.forename: M P
authors.initials: MP
authors.lastname: Guerrero-Lebrero
authors.affiliation: School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia.
authors.forename: A J
authors.initials: AJ
authors.lastname: D'Alfonso
authors.affiliation: JEOL Ltd., 1-2 Musashino 3-Chome, Akishima, 196-8558 Tokyo, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Yasuhara
authors.affiliation: JEOL Ltd., 1-2 Musashino 3-Chome, Akishima, 196-8558 Tokyo, Japan.
authors.forename: E
authors.initials: E
authors.lastname: Okunishi
authors.affiliation: Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, CB3 0FS Cambridge, United Kingdom.
authors.forename: S
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, CB3 0FS Cambridge, United Kingdom.
authors.forename: C J
authors.initials: CJ
authors.lastname: Humphreys
authors.affiliation: School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia.
authors.forename: L J
authors.initials: LJ
authors.lastname: Allen
authors.affiliation: Departamento de Ingeniería Informática, CASEM, Universidad de Cadiz, Polígono Rio San Pedro s/n, 11510 Puerto Real (Cadiz), Spain.
authors.forename: P L
authors.initials: PL
authors.lastname: Galindo
authors.affiliation: Department of Materials, University of Oxford, OX1 3PH Oxford, United Kingdom.
authors.forename: P B
authors.initials: PB
authors.lastname: Hirsch
authors.affiliation: Department of Materials, University of Oxford, OX1 3PH Oxford, United Kingdom.
authors.forename: P D
authors.initials: PD
authors.lastname: Nellist