Regensburg 2013 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 40: Topical Session: TEM-Symposium - In-Situ I
MM 40.2: Talk
Wednesday, March 13, 2013, 15:30–15:45, H25
Birth, motion, interaction, and annihilation of dislocations in graphene at the atomic scale — •Ossi Lehtinen1,2, Simon Kurasch1, Arkady V. Krasheninnikov2,3, and Ute Kaiser1 — 1Central Facility for Electron Microscopy, Group of Electron Microscopy of Materials Science, University of Ulm — 2Department of Physics, University of Helsinki, Finland — 3Department of Applied Physics, Aalto University
Dislocations, one of the key concepts in materials science, govern the mechanical properties of any material. Thus, understanding their life cycle, from creation to annihilation via motion and interaction with other dislocations, point defects, and surfaces is of fundamental importance. Unfortunately, atomic scale investigations of dislocation evolution in a bulk object are well beyond the spatial and temporal resolution limits of current characterization techniques, and therefore such studies have long been reserved for computer simulations and analytical theory. Here, we overcome the experimental limits by investigating a two-dimensional material, graphene, in an aberration-corrected transmission electron microscope, exploiting the impinging energetic electrons both to image and stimulate atomic scale morphological changes in the material. The resulting transformations are followed in-situ, showing the full life cycle of a dislocation from birth to annihilation. Our experiment, combined with atomistic simulations, reveals the underlying mechanism of interaction to be out-of-plane buckling, which leads to markedly long-range interactions of the defects.