Stoichiometric reconstruction of the Al 2 O 3 (0001) surface

Macroscopic properties of materials stem from fundamental atomic-scale details, yet for insulators, resolving surface structures remains a challenge. We imaged the basal (0001) plane of α-aluminum oxide (α-Al O ) using noncontact atomic force microscopy with an atomically defined tip apex. The surfa...

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Bibliographic Details
Published in:Science (American Association for the Advancement of Science) 2024-09, Vol.385 (6714), p.1241-1244
Main Authors: Hütner, Johanna I, Conti, Andrea, Kugler, David, Mittendorfer, Florian, Kresse, Georg, Schmid, Michael, Diebold, Ulrike, Balajka, Jan
Format: Article
Language:English
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Summary:Macroscopic properties of materials stem from fundamental atomic-scale details, yet for insulators, resolving surface structures remains a challenge. We imaged the basal (0001) plane of α-aluminum oxide (α-Al O ) using noncontact atomic force microscopy with an atomically defined tip apex. The surface formed a complex ([Formula: see text] × [Formula: see text]) ±9° reconstruction. The lateral positions of the individual oxygen and aluminum surface atoms come directly from experiment; we determined with computational modeling how these connect to the underlying crystal bulk. Before the restructuring, the surface Al atoms assume an unfavorable, threefold planar coordination; the reconstruction allows a rehybridization with subsurface O that leads to a substantial energy gain. The reconstructed surface remains stoichiometric, Al O .
ISSN:0036-8075
1095-9203
DOI:10.1126/science.adq4744