Stoichiometric reconstruction of the Al2O3(0001) surface

• 成果类型: Article
• 署名作者: Huetner, Johanna I.; Conti, Andrea; Kugler, David; Mittendorfer, Florian; Kresse, Georg; Schmid, Michael; Diebold, Ulrike; Balajka, Jan
• 署名单位: Technische Universitat Wien; University of Vienna
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-9573
• DOI: 10.1126/science.adq4744
• 发表日期: 2024-09-13
• 页码: 1241-1244
• 关键词: 0001 face; alpha-al2o3

摘要

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 alpha-aluminum oxide (alpha-Al2O3) using noncontact atomic force microscopy with an atomically defined tip apex. The surface formed a complex (root 31 x root 31)R +/- 9 degrees 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, Al2O3.