title: A journey from order to disorder - atom by atom transformation from graphene to a 2D carbon glass.
abstract: One of the most interesting questions in solid state theory is the structure of glass, which has eluded researchers since the early 1900's. Since then, two competing models, the random network theory and the crystallite theory, have both gathered experimental support. Here, we present a direct, atomic-level structural analysis during a crystal-to-glass transformation, including all intermediate stages. We introduce disorder on a 2D crystal, graphene, gradually, utilizing the electron beam of a transmission electron microscope, which allows us to capture the atomic structure at each step. The change from a crystal to a glass happens suddenly, and at a surprisingly early stage. Right after the transition, the disorder manifests as a vitreous network separating individual crystallites, similar to the modern version of the crystallite theory. However, upon increasing disorder, the vitreous areas grow on the expense of the crystallites and the structure turns into a random network. Thereby, our results show that, at least in the case of a 2D structure, both of the models can be correct, and can even describe the same material at different degrees of disorder.
authors: Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria.
authors: Franz R
authors: FR
authors: Eder
authors: 1] Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria [2] Department of Physics, P.O. Box 43, 00014 University of Helsinki, Finland.
authors: Jani
authors: J
authors: Kotakoski
authors: Central Facility for Electron Microscopy, Group of Electron Microscopy of Materials Science, University of Ulm, Albert Einstein Allee 11, 89081 Ulm, Germany.
authors: Ute
authors: U
authors: Kaiser
authors: 1] Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria [2] Central Facility for Electron Microscopy, Group of Electron Microscopy of Materials Science, University of Ulm, Albert Einstein Allee 11, 89081 Ulm, Germany.
authors: Jannik C
authors: JC
authors: Meyer