title: Silicon-carbon bond inversions driven by 60-keV electrons in graphene.
abstract: We demonstrate that 60-keV electron irradiation drives the diffusion of threefold-coordinated Si dopants in graphene by one lattice site at a time. First principles simulations reveal that each step is caused by an electron impact on a C atom next to the dopant. Although the atomic motion happens below our experimental time resolution, stochastic analysis of 38 such lattice jumps reveals a probability for their occurrence in a good agreement with the simulations. Conversions from three- to fourfold coordinated dopant structures and the subsequent reverse process are significantly less likely than the direct bond inversion. Our results thus provide a model of nondestructive and atomically precise structural modification and detection for two-dimensional materials.
authors.affiliation: Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria.
authors.forename: Toma
authors.initials: T
authors.lastname: Susi
authors.affiliation: Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria and Department of Physics, University of Helsinki, P.O. Box 43, FI-00014 Helsinki, Finland.
authors.forename: Jani
authors.initials: J
authors.lastname: Kotakoski
authors.affiliation: SuperSTEM Laboratory, STFC Daresbury Campus, Daresbury WA4 4AD, United Kingdom.
authors.forename: Demie
authors.initials: D
authors.lastname: Kepaptsoglou
authors.affiliation: Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria.
authors.forename: Clemens
authors.initials: C
authors.lastname: Mangler
authors.affiliation: Nion Co., 1102 8th Street, Kirkland, Washington 98033, USA.
authors.forename: Tracy C
authors.initials: TC
authors.lastname: Lovejoy
authors.affiliation: Nion Co., 1102 8th Street, Kirkland, Washington 98033, USA.
authors.forename: Ondrej L
authors.initials: OL
authors.lastname: Krivanek
authors.affiliation: School of Materials, The University of Manchester, Manchester M13 9PL, United Kingdom and Department of Physics, Faculty of Arts and Sciences, Niğde University, 51000 Niğde, Turkey.
authors.forename: Recep
authors.initials: R
authors.lastname: Zan
authors.affiliation: School of Materials, The University of Manchester, Manchester M13 9PL, United Kingdom and Department of Physics and Energy, University of Limerick, Limerick, Ireland.
authors.forename: Ursel
authors.initials: U
authors.lastname: Bangert
authors.affiliation: Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria.
authors.forename: Paola
authors.initials: P
authors.lastname: Ayala
authors.affiliation: Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria.
authors.forename: Jannik C
authors.initials: JC
authors.lastname: Meyer
authors.affiliation: SuperSTEM Laboratory, STFC Daresbury Campus, Daresbury WA4 4AD, United Kingdom.
authors.forename: Quentin
authors.initials: Q
authors.lastname: Ramasse