Spatially resolved electronic structure of twisted graphene

Qirong Yao, Rik Van Bremen, Guus J. Slotman, Lijie Zhang, Sebastiaan Haartsen, Kai Sotthewes, Pantelis Bampoulis, Paul L. De Boeij, Arie Van Houselt, Shengjun Yuan, Harold J.W. Zandvliet

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Abstract

We have used scanning tunneling microscopy and spectroscopy to resolve the spatial variation of the density of states of twisted graphene layers on top of a highly oriented pyrolytic graphite substrate. Owing to the twist a moiré pattern develops with a periodicity that is substantially larger than the periodicity of a single layer graphene. The twisted graphene layer has electronic properties that are distinctly different from that of a single layer graphene due to the nonzero interlayer coupling. For small twist angles (∼1-3.5) the integrated differential conductivity spectrum exhibits two well-defined Van Hove singularities. Spatial maps of the differential conductivity that are recorded at energies near the Fermi level exhibit a honeycomb structure that is comprised of two inequivalent hexagonal sublattices. For energies |E-EF|>0.3eV the hexagonal structure in the differential conductivity maps vanishes. We have performed tight-binding calculations of the twisted graphene system using the propagation method, in which a third graphene layer is added to mimic the substrate. This third layer lowers the symmetry and explains the development of the two hexagonal sublattices in the moiré pattern. Our experimental results are in excellent agreement with the tight-binding calculations.

Original languageEnglish
Article number245116
JournalPhysical review B: Covering condensed matter and materials physics
Volume95
Issue number24
DOIs
Publication statusPublished - 15 Jun 2017

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Graphite
Graphene
Electronic structure
graphene
electronic structure
conductivity
sublattices
periodic variations
Honeycomb structures
honeycomb structures
pyrolytic graphite
Scanning tunneling microscopy
Substrates
Fermi level
trucks
Electronic properties
scanning tunneling microscopy
interlayers
Spectroscopy
propagation

Cite this

@article{680f21ca9dd5496eb05aeacf32a7b196,
title = "Spatially resolved electronic structure of twisted graphene",
abstract = "We have used scanning tunneling microscopy and spectroscopy to resolve the spatial variation of the density of states of twisted graphene layers on top of a highly oriented pyrolytic graphite substrate. Owing to the twist a moir{\'e} pattern develops with a periodicity that is substantially larger than the periodicity of a single layer graphene. The twisted graphene layer has electronic properties that are distinctly different from that of a single layer graphene due to the nonzero interlayer coupling. For small twist angles (∼1-3.5) the integrated differential conductivity spectrum exhibits two well-defined Van Hove singularities. Spatial maps of the differential conductivity that are recorded at energies near the Fermi level exhibit a honeycomb structure that is comprised of two inequivalent hexagonal sublattices. For energies |E-EF|>0.3eV the hexagonal structure in the differential conductivity maps vanishes. We have performed tight-binding calculations of the twisted graphene system using the propagation method, in which a third graphene layer is added to mimic the substrate. This third layer lowers the symmetry and explains the development of the two hexagonal sublattices in the moir{\'e} pattern. Our experimental results are in excellent agreement with the tight-binding calculations.",
author = "Qirong Yao and {Van Bremen}, Rik and Slotman, {Guus J.} and Lijie Zhang and Sebastiaan Haartsen and Kai Sotthewes and Pantelis Bampoulis and {De Boeij}, {Paul L.} and {Van Houselt}, Arie and Shengjun Yuan and Zandvliet, {Harold J.W.}",
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month = "6",
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language = "English",
volume = "95",
journal = "Physical review B: Covering condensed matter and materials physics",
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}

Spatially resolved electronic structure of twisted graphene. / Yao, Qirong; Van Bremen, Rik; Slotman, Guus J.; Zhang, Lijie; Haartsen, Sebastiaan; Sotthewes, Kai; Bampoulis, Pantelis; De Boeij, Paul L.; Van Houselt, Arie; Yuan, Shengjun; Zandvliet, Harold J.W.

In: Physical review B: Covering condensed matter and materials physics, Vol. 95, No. 24, 245116, 15.06.2017.

Research output: Contribution to journalArticleAcademicpeer-review

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T1 - Spatially resolved electronic structure of twisted graphene

AU - Yao, Qirong

AU - Van Bremen, Rik

AU - Slotman, Guus J.

AU - Zhang, Lijie

AU - Haartsen, Sebastiaan

AU - Sotthewes, Kai

AU - Bampoulis, Pantelis

AU - De Boeij, Paul L.

AU - Van Houselt, Arie

AU - Yuan, Shengjun

AU - Zandvliet, Harold J.W.

PY - 2017/6/15

Y1 - 2017/6/15

N2 - We have used scanning tunneling microscopy and spectroscopy to resolve the spatial variation of the density of states of twisted graphene layers on top of a highly oriented pyrolytic graphite substrate. Owing to the twist a moiré pattern develops with a periodicity that is substantially larger than the periodicity of a single layer graphene. The twisted graphene layer has electronic properties that are distinctly different from that of a single layer graphene due to the nonzero interlayer coupling. For small twist angles (∼1-3.5) the integrated differential conductivity spectrum exhibits two well-defined Van Hove singularities. Spatial maps of the differential conductivity that are recorded at energies near the Fermi level exhibit a honeycomb structure that is comprised of two inequivalent hexagonal sublattices. For energies |E-EF|>0.3eV the hexagonal structure in the differential conductivity maps vanishes. We have performed tight-binding calculations of the twisted graphene system using the propagation method, in which a third graphene layer is added to mimic the substrate. This third layer lowers the symmetry and explains the development of the two hexagonal sublattices in the moiré pattern. Our experimental results are in excellent agreement with the tight-binding calculations.

AB - We have used scanning tunneling microscopy and spectroscopy to resolve the spatial variation of the density of states of twisted graphene layers on top of a highly oriented pyrolytic graphite substrate. Owing to the twist a moiré pattern develops with a periodicity that is substantially larger than the periodicity of a single layer graphene. The twisted graphene layer has electronic properties that are distinctly different from that of a single layer graphene due to the nonzero interlayer coupling. For small twist angles (∼1-3.5) the integrated differential conductivity spectrum exhibits two well-defined Van Hove singularities. Spatial maps of the differential conductivity that are recorded at energies near the Fermi level exhibit a honeycomb structure that is comprised of two inequivalent hexagonal sublattices. For energies |E-EF|>0.3eV the hexagonal structure in the differential conductivity maps vanishes. We have performed tight-binding calculations of the twisted graphene system using the propagation method, in which a third graphene layer is added to mimic the substrate. This third layer lowers the symmetry and explains the development of the two hexagonal sublattices in the moiré pattern. Our experimental results are in excellent agreement with the tight-binding calculations.

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