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O: Fachverband Oberflächenphysik
O 55: Oxide and insulator surfaces: Structure, epitaxy and growth II
O 55.4: Vortrag
Mittwoch, 11. März 2026, 11:30–11:45, HSZ/0204
Surface reconstruction of the polar spinel MgAl2O4(001) surface — David Kugler1, Andrea Conti1, Johanna I. Hütner-Reisch1, Soumyajit Rajak2, Matthias Meier1, Nan Jiang2, Florian Mittendorfer1, Michael Schmid1, Ulrike Diebold1, Gareth S. Parkinson1, and •Jan Balajka1 — 1Institute of Applied Physics, TU Wien, Vienna, Austria — 2Department of Chemistry, University of Illinois Chicago, USA
The atomic-scale surface structure governs the surface chemistry of materials. Magnesium aluminate (MgAl2O4) spinel, a wide-gap insulator, poses considerable challenges for experimental surface characterization. Using noncontact atomic force microscopy (nc-AFM), we resolve the atomic structure of the MgAl2O4(001) surface. The surface adopts a c(2×4) reconstruction accompanied by altered surface stoichiometry. The reconstructed surface is enriched in aluminum and contains ordered pairs of octahedrally coordinated Mg atoms that, in bulk, occupy tetrahedral sites. This cation redistribution stabilizes the otherwise polar MgAl2O4(001) termination. The resulting structure closely resembles reconstructions observed on other spinel oxides, suggesting a common mechanism for polarity compensation across the spinel group.
Keywords: surface structure; polar surfaces; spinel MgAl2O4; noncontact AFM; scanning probe microscopy