Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 45: Graphene: Adsorption, Intercalation and Doping
O 45.4: Poster
Dienstag, 8. März 2016, 18:15–20:30, Poster E
Band gap engineering by Bi intercalation of graphene on Ir(111) — •Jonas Warmuth1, Matteo Michiardi2, Albert Bruix Fusté2, Torben Hänke1, Marco Bianchi2, Jens Wiebe1, Roland Wiesendanger1, Bjørk Hammer2, Philip Hofmann2, and Alexander Ako Khajetoorians3,2 — 1Dept. of Physics, Hamburg University, Hamburg, Germany — 2Interdisciplinary Nanoscience Center and Department of Physics and Astronomy, Aarhus University, Denmark — 3Institute of Molecules and Materials, Radboud University, Nijmegen, Netherlands
We report on the structural and electronic properties of a single bismuth layer intercalated underneath a graphene layer grown on an Ir(111) single crystal. Scanning tunneling microscopy (STM) reveals a hexagonal surface structure and a dislocation network upon Bi intercalation, which we attribute to a √3×√3R30∘ Bi reconstruction on the underlying Ir(111) surface. Ab-initio calculations show that this Bi reconstruction is the most energetically favorable, and also illustrate that STM measurements are most sensitive to C atoms in close proximity to intercalated Bi atoms. Additionally, Bi intercalation induces a band gap (Eg=0.42 eV) at the Dirac point of graphene and an overall n-doping (0.39 eV), as seen in angular-resolved photoemission spectroscopy. We attribute the emergence of the band gap to the dislocation network which forms favorably along certain parts of the moiré structure induced by the graphene/Ir(111) interface.