Cargando…

Moiré Superlattice Effects and Band Structure Evolution in Near-30-Degree Twisted Bilayer Graphene

[Image: see text] In stacks of two-dimensional crystals, mismatch of their lattice constants and misalignment of crystallographic axes lead to formation of moiré patterns. We show that moiré superlattice effects persist in twisted bilayer graphene (tBLG) with large twists and short moiré periods. Us...

Descripción completa

Detalles Bibliográficos
Autores principales: Hamer, Matthew J., Giampietri, Alessio, Kandyba, Viktor, Genuzio, Francesca, Menteş, Tevfik O., Locatelli, Andrea, Gorbachev, Roman V., Barinov, Alexei, Mucha-Kruczyński, Marcin
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2022
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9007532/
https://www.ncbi.nlm.nih.gov/pubmed/35073479
http://dx.doi.org/10.1021/acsnano.1c06439
_version_ 1784686870676897792
author Hamer, Matthew J.
Giampietri, Alessio
Kandyba, Viktor
Genuzio, Francesca
Menteş, Tevfik O.
Locatelli, Andrea
Gorbachev, Roman V.
Barinov, Alexei
Mucha-Kruczyński, Marcin
author_facet Hamer, Matthew J.
Giampietri, Alessio
Kandyba, Viktor
Genuzio, Francesca
Menteş, Tevfik O.
Locatelli, Andrea
Gorbachev, Roman V.
Barinov, Alexei
Mucha-Kruczyński, Marcin
author_sort Hamer, Matthew J.
collection PubMed
description [Image: see text] In stacks of two-dimensional crystals, mismatch of their lattice constants and misalignment of crystallographic axes lead to formation of moiré patterns. We show that moiré superlattice effects persist in twisted bilayer graphene (tBLG) with large twists and short moiré periods. Using angle-resolved photoemission, we observe dramatic changes in valence band topology across large regions of the Brillouin zone, including the vicinity of the saddle point at M and across 3 eV from the Dirac points. In this energy range, we resolve several moiré minibands and detect signatures of secondary Dirac points in the reconstructed dispersions. For twists θ > 21.8°, the low-energy minigaps are not due to cone anticrossing as is the case at smaller twist angles but rather due to moiré scattering of electrons in one graphene layer on the potential of the other which generates intervalley coupling. Our work demonstrates the robustness of the mechanisms which enable engineering of electronic dispersions of stacks of two-dimensional crystals by tuning the interface twist angles. It also shows that large-angle tBLG hosts electronic minigaps and van Hove singularities of different origin which, given recent progress in extreme doping of graphene, could be explored experimentally.
format Online
Article
Text
id pubmed-9007532
institution National Center for Biotechnology Information
language English
publishDate 2022
publisher American Chemical Society
record_format MEDLINE/PubMed
spelling pubmed-90075322022-04-14 Moiré Superlattice Effects and Band Structure Evolution in Near-30-Degree Twisted Bilayer Graphene Hamer, Matthew J. Giampietri, Alessio Kandyba, Viktor Genuzio, Francesca Menteş, Tevfik O. Locatelli, Andrea Gorbachev, Roman V. Barinov, Alexei Mucha-Kruczyński, Marcin ACS Nano [Image: see text] In stacks of two-dimensional crystals, mismatch of their lattice constants and misalignment of crystallographic axes lead to formation of moiré patterns. We show that moiré superlattice effects persist in twisted bilayer graphene (tBLG) with large twists and short moiré periods. Using angle-resolved photoemission, we observe dramatic changes in valence band topology across large regions of the Brillouin zone, including the vicinity of the saddle point at M and across 3 eV from the Dirac points. In this energy range, we resolve several moiré minibands and detect signatures of secondary Dirac points in the reconstructed dispersions. For twists θ > 21.8°, the low-energy minigaps are not due to cone anticrossing as is the case at smaller twist angles but rather due to moiré scattering of electrons in one graphene layer on the potential of the other which generates intervalley coupling. Our work demonstrates the robustness of the mechanisms which enable engineering of electronic dispersions of stacks of two-dimensional crystals by tuning the interface twist angles. It also shows that large-angle tBLG hosts electronic minigaps and van Hove singularities of different origin which, given recent progress in extreme doping of graphene, could be explored experimentally. American Chemical Society 2022-01-24 2022-02-22 /pmc/articles/PMC9007532/ /pubmed/35073479 http://dx.doi.org/10.1021/acsnano.1c06439 Text en © 2022 American Chemical Society https://creativecommons.org/licenses/by/4.0/Permits the broadest form of re-use including for commercial purposes, provided that author attribution and integrity are maintained (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Hamer, Matthew J.
Giampietri, Alessio
Kandyba, Viktor
Genuzio, Francesca
Menteş, Tevfik O.
Locatelli, Andrea
Gorbachev, Roman V.
Barinov, Alexei
Mucha-Kruczyński, Marcin
Moiré Superlattice Effects and Band Structure Evolution in Near-30-Degree Twisted Bilayer Graphene
title Moiré Superlattice Effects and Band Structure Evolution in Near-30-Degree Twisted Bilayer Graphene
title_full Moiré Superlattice Effects and Band Structure Evolution in Near-30-Degree Twisted Bilayer Graphene
title_fullStr Moiré Superlattice Effects and Band Structure Evolution in Near-30-Degree Twisted Bilayer Graphene
title_full_unstemmed Moiré Superlattice Effects and Band Structure Evolution in Near-30-Degree Twisted Bilayer Graphene
title_short Moiré Superlattice Effects and Band Structure Evolution in Near-30-Degree Twisted Bilayer Graphene
title_sort moiré superlattice effects and band structure evolution in near-30-degree twisted bilayer graphene
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9007532/
https://www.ncbi.nlm.nih.gov/pubmed/35073479
http://dx.doi.org/10.1021/acsnano.1c06439
work_keys_str_mv AT hamermatthewj moiresuperlatticeeffectsandbandstructureevolutioninnear30degreetwistedbilayergraphene
AT giampietrialessio moiresuperlatticeeffectsandbandstructureevolutioninnear30degreetwistedbilayergraphene
AT kandybaviktor moiresuperlatticeeffectsandbandstructureevolutioninnear30degreetwistedbilayergraphene
AT genuziofrancesca moiresuperlatticeeffectsandbandstructureevolutioninnear30degreetwistedbilayergraphene
AT mentestevfiko moiresuperlatticeeffectsandbandstructureevolutioninnear30degreetwistedbilayergraphene
AT locatelliandrea moiresuperlatticeeffectsandbandstructureevolutioninnear30degreetwistedbilayergraphene
AT gorbachevromanv moiresuperlatticeeffectsandbandstructureevolutioninnear30degreetwistedbilayergraphene
AT barinovalexei moiresuperlatticeeffectsandbandstructureevolutioninnear30degreetwistedbilayergraphene
AT muchakruczynskimarcin moiresuperlatticeeffectsandbandstructureevolutioninnear30degreetwistedbilayergraphene