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Mini-Dirac cones in the band structure of a copper intercalated epitaxial graphene superlattice

Forti, S.; Stöhr, A.; Zakharov, A. A. LU ; Coletti, C.; Emtsev, K. V. and Starke, U. (2016) In 2D Materials 3(3).
Abstract

The electronic band structure of an epitaxial graphene superlattice, generated by intercalating a monolayer of Cu atoms, is directly imaged by angle-resolved photoelectron spectroscopy. The 3.2 nm lateral period of the superlattice is induced by a varying registry between the graphene honeycomb and the Cu atoms as imposed by the heteroepitaxial interface Cu/SiC. The carbon atoms experience a lateral potential across the supercell of an estimated value of about 65 meV. The potential leads to strong energy renormalization in the band structure of the graphene layer and the emergence of mini-Dirac cones. The mini-cones' band velocity is reduced to about half of graphene's Fermi velocity. Notably, the ordering of the interfacial Cu atoms... (More)

The electronic band structure of an epitaxial graphene superlattice, generated by intercalating a monolayer of Cu atoms, is directly imaged by angle-resolved photoelectron spectroscopy. The 3.2 nm lateral period of the superlattice is induced by a varying registry between the graphene honeycomb and the Cu atoms as imposed by the heteroepitaxial interface Cu/SiC. The carbon atoms experience a lateral potential across the supercell of an estimated value of about 65 meV. The potential leads to strong energy renormalization in the band structure of the graphene layer and the emergence of mini-Dirac cones. The mini-cones' band velocity is reduced to about half of graphene's Fermi velocity. Notably, the ordering of the interfacial Cu atoms can be reversibly blocked by mild annealing. The superlattice indeed disappears at∼220 °C.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Epitaxial graphene, Graphene, Intercalation, Photoemission, Superlattice
in
2D Materials
volume
3
issue
3
publisher
IOP Publishing
external identifiers
  • scopus:84992427939
ISSN
2053-1583
DOI
10.1088/2053-1583/3/3/035003
language
English
LU publication?
yes
id
7d76cb60-7a98-4b48-9754-e33dc08ba92f
date added to LUP
2017-01-12 14:31:02
date last changed
2017-07-09 04:57:04
@article{7d76cb60-7a98-4b48-9754-e33dc08ba92f,
  abstract     = {<p>The electronic band structure of an epitaxial graphene superlattice, generated by intercalating a monolayer of Cu atoms, is directly imaged by angle-resolved photoelectron spectroscopy. The 3.2 nm lateral period of the superlattice is induced by a varying registry between the graphene honeycomb and the Cu atoms as imposed by the heteroepitaxial interface Cu/SiC. The carbon atoms experience a lateral potential across the supercell of an estimated value of about 65 meV. The potential leads to strong energy renormalization in the band structure of the graphene layer and the emergence of mini-Dirac cones. The mini-cones' band velocity is reduced to about half of graphene's Fermi velocity. Notably, the ordering of the interfacial Cu atoms can be reversibly blocked by mild annealing. The superlattice indeed disappears at∼220 °C.</p>},
  articleno    = {035003},
  author       = {Forti, S. and Stöhr, A. and Zakharov, A. A. and Coletti, C. and Emtsev, K. V. and Starke, U.},
  issn         = {2053-1583},
  keyword      = {Epitaxial graphene,Graphene,Intercalation,Photoemission,Superlattice},
  language     = {eng},
  month        = {07},
  number       = {3},
  publisher    = {IOP Publishing},
  series       = {2D Materials},
  title        = {Mini-Dirac cones in the band structure of a copper intercalated epitaxial graphene superlattice},
  url          = {http://dx.doi.org/10.1088/2053-1583/3/3/035003},
  volume       = {3},
  year         = {2016},
}