Dirac cone manipulation via bismuth and oxygen intercalation underneath graphene on Re(0001)

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Abstract

This paper reports on an investigation by angle-resolved photoelectron spectroscopy of the graphene on Re(0001) substrate, after intercalation by bismuth atoms. Our results demonstrate that intercalation of Bi atoms restores the quasi-free-standing
properties of graphene. Thus, the band structure of this system is characterized by a linear π-state dispersion near the K point of the
Brillouin zone. The Dirac point shifts toward higher binding energies by approximately 0.4 eV, which is caused by charge transfer
from Bi atoms to graphene. Besides we observed a band gap with a width of at least 0.4 eV. The possible reasons of the band gap
in the system Gr/Bi/Re(0001) can be caused by hybridization of π-states of graphene with 5d-rhenium states and/or bismuth states
or symmetry breaking of the sublattices of graphene. Moreover, the Dirac point position is found to be different depending on the
intercalated atoms. Intercalation of the oxygen atoms underneath graphene after exposure to the air results in the appearance of the
second π-state branch in the electronic structure. There are two Dirac cones in the ARPES image and for the first one the charge
transfer from the Bi atoms leads to the Dirac point position below the Fermi level, i.e. to the n-doping of graphene. For the second
one the Dirac point is located above the Fermi level resulting in p-doping that is caused by charge transfer between oxygen and
graphene atoms.
Original languageEnglish
Article number02008
Number of pages3
JournalAIP Conference Proceedings
Volume2359
Issue number1
StatePublished - 2021
EventInternational Congress on Graphene, 2D Materials and Applications (2D Materials 2019) - Сочи, Russian Federation
Duration: 30 Sep 20194 Oct 2019
http://2dmaterials-congress.com/

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