Berlin 2018 – scientific programme
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O: Fachverband Oberflächenphysik
O 103: Oxide and Insulator Surfaces: Structure, Epitaxy and Growth II
O 103.3: Talk
Thursday, March 15, 2018, 16:15–16:30, MA 041
The structure of a two dimensional silica ’zigzag’ polymorph on Ruthenium — •David Kuhness1, Hyun Jin Yang1, Hagen Klemm1, Mauricio Prieto1, Xin Yu1, Denis Usvyat2, Martin Schütz2, Dietrich Menzel1, Shamil Shaikhudtinov1, Thomas Schmidt1, Markus Heyde1, Joachim Sauer2, and Hans-Joachim Freund1 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany — 2Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany
Ultrathin two dimensional silica films grown on metal substrates serve as a model system for the study of glass. Its detailed study at the atomic scale allows for insights into its atomic structure, its growth modes, transformations and the herein involved dynamics. We here present a new two dimensional silica polymorph grown on a Ru(0001) metal substrate with characteristic ’zigzag’ line structure and rectangular unit cell. Based on scanning tunneling microscopy, low energy electron diffraction, infrared reflection absorption spectroscopy and x-ray photo-electron spectroscopy measurements on the one hand, and density functional theory calculations on the other, a structural model for the ’zigzag’ polymorph is proposed. In comparison to established monolayer and bilayer silica, this ’zigzag’ structure system has intermediate characteristics in terms of coupling to the substrate and stoichiometry. The silica ’zigzag’ phase is transformed upon reoxidation at higher annealing temperature into a SiO2 silica bilayer film which is chemically decoupled from the substrate.