Twistronics of Kekulé Graphene: Honeycomb and Kagome Flat Bands.
Phys Rev Lett
; 131(26): 266501, 2023 Dec 29.
Article
em En
| MEDLINE
| ID: mdl-38215385
ABSTRACT
Kekulé-O order in graphene, which has recently been realized experimentally, induces Dirac electron masses on the order of mâ¼100 meV. We show that twisted bilayer graphene in which one or both layers have Kekulé-O order exhibits nontrivial flat electronic bands on honeycomb and kagome lattices. When only one layer has Kekulé-O order, there is a parameter regime for which the lowest four bands at charge neutrality form an isolated two-orbital honeycomb lattice model with two flat bands. The bandwidths are minimal at a magic twist angle θ≈0.7° and Dirac mass m≈100 meV. When both layers have Kekulé-O order, there is a large parameter regime around θ≈1° and mâ³100 meV in which the lowest three valence and conduction bands at charge neutrality each realize isolated kagome lattice models with one flat band, while the next three valence and conduction bands are flat bands on triangular lattices. These flat band systems may provide a new platform for strongly correlated phases of matter.
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MEDLINE
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En
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Phys Rev Lett
Ano de publicação:
2023
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Article