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arXiv · 1603.08724

Band gap engineering by Bi intercalation of graphene on Ir(111)

Jonas Warmuth·Albert Bruix·Matteo Michiardi·Torben Hänke·Marco Bianchi·Jens Wiebe·Roland Wiesendanger·Bjørk Hammer·Philip Hofmann·Alexander A. Khajetoorians
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Abstract

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 $\sqrt{3}\times\sqrt{3}R30{\deg}$ Bi structure on the underlying Ir(111) surface. Ab-initio calculations show that this Bi structure 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 ($E_g=0.42\,$eV) at the Dirac point of graphene and an overall n-doping ($\sim 0.39\,$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 moir\'e structure induced by the graphene/Ir(111) interface.

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Jonas Warmuth, Albert Bruix, Matteo Michiardi, Torben Hänke, Marco Bianchi, Jens Wiebe, Roland Wiesendanger, Bjørk Hammer, Philip Hofmann, Alexander A. Khajetoorians. 2016-03-29. Band gap engineering by Bi intercalation of graphene on Ir(111). https://doi.org/10.1103/physrevb.93.165437

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