SKM 2023 – scientific programme
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O: Fachverband Oberflächenphysik
O 68: Poster: Oxide and Insulator Surfaces
O 68.2: Poster
Wednesday, March 29, 2023, 18:00–20:00, P2/EG
Ab-initio investigations of the order of K+ ions on cleaved muscovite mica — •Andrea Conti, Giada Franceschi, Michael Schmid, Ulrike Diebold, and Florian Mittendorfer — Institute of Applied Physics, TU Wien, Wiedner Hauptstrasse 8-10/134, 1040 Vienna, Austria
Model systems based on single crystals can help to provide a better understanding of the chemistry and the catalytic activity of a given oxide surface. In this work, we present DFT calculations on the surface of muscovite mica, a common phyllosilicate whose structure consists of alternating layers of aluminosilicates and K+ ions. This material easily splits into thin K-terminated sheets, yet the atomistic order of the surface K+ ions has been, until recently, unknown [Franceschi et al., submitted (2022)]. Calculations, using the “Vienna Ab-initio Simulation Package” (VASP) and the metaGGA (r2SCAN) exchange-correlation functional, indicate a close correlation between the distribution of the surface K+ ions and the arrangements of the subsurface Al3+ ions: the K+ ions preferentially occupy the Al-rich rings. In addition, the calculated diffusion barriers suggest that the K+ ions are mobile enough at room temperature to jump to more favorable sites. AFM simulations, using the Probe Particle Model, are in good agreement with the experimental images.