Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 21: Graphene - Electronic Properties and Transport 1 (jointly with DS, HL, MA, and O)
TT 21.1: Vortrag
Montag, 11. März 2013, 16:00–16:15, H17
Epitaxial silicene - tunable hybridization with the substrate and weak interactions with epitaxial organic overlayers — •Rainer Friedlein1, Antoine Fleurence1, Fabio Bussolotti1,2, and Yukiko Yamada-Takamura1 — 1School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), Nomi, Ishikawa 923-1292, Japan — 2present address: Graduate School of Advanced Integration Science, Chiba University, Chiba, Japan
The electronic and structural properties of epitaxial silicene formed on ZrB2(0001) thin films grown on Si(111) wafers upon adsorption of either potassium atoms and anthracene molecules have been studied using photoelectron spectroscopy and electron diffraction. For pristine silicene, a particular, atomic-scale buckling leads to the opening of a direct band gap at the Γ point, while ZrB2-related surface states are not affected. This is consistent with only a minor degree of hybridization beween Si- and Zr-derived states. The electronic interactions at the interface can be tuned by electron donation from adsorbed potassium atoms, upon which hybridization is progressively switched on.
At 140 K, anthracene molecules are found to grow as epitaxial multilayers that exhibit a point-on-line commensurate relationship with silicene. The results indicate that the charge-density modulation associated with the buckling of silicene render the interactions with organic adsorbates as compared to graphene, which allows for specific epitaxial conditions. On the other hand, the results also confirm that silicene is strikingly different from other Si surfaces for which the presence of dangling bonds leads to chemisorption of organic adsorbates.