Extended magic phase in twisted graphene multilayers

Fuente: arXiv
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Autori principali: Foo, D. C. W., Zhan, Z., Ezzi, Mohammed M. Al, Peng, L., Adam, S., Guinea, F.
Natura: Preprint
Pubblicazione: 2023
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author Foo, D. C. W.
Zhan, Z.
Ezzi, Mohammed M. Al
Peng, L.
Adam, S.
Guinea, F.
author_facet Foo, D. C. W.
Zhan, Z.
Ezzi, Mohammed M. Al
Peng, L.
Adam, S.
Guinea, F.
contents Theoretical and experimental studies have verified the existence of ``magic angles'' in twisted bilayer graphene, where the twist between layers gives rise to flat bands and consequently highly correlated phases. Narrow bands can also exist in multilayers with alternating twist angles, and recent theoretical work suggests that they can also be found in trilayers with twist angles between neighboring layers in the same direction. We show here that flat bands exist in a variety of multilayers where the ratio between twist angles is close to coprime integers. We generalize previous analyses, and, using the chiral limit for interlayer coupling, give examples of many combinations of twist angles in stacks made up of three and four layers which lead to flat bands. The technique we use can be extended to systems with many layers. Our results suggest that flat bands can exist in graphene multilayers with angle disorder, that is, narrow samples of turbostatic graphite.
format Preprint
id arxiv_https___arxiv_org_abs_2305_18080
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Extended magic phase in twisted graphene multilayers
Foo, D. C. W.
Zhan, Z.
Ezzi, Mohammed M. Al
Peng, L.
Adam, S.
Guinea, F.
Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
Theoretical and experimental studies have verified the existence of ``magic angles'' in twisted bilayer graphene, where the twist between layers gives rise to flat bands and consequently highly correlated phases. Narrow bands can also exist in multilayers with alternating twist angles, and recent theoretical work suggests that they can also be found in trilayers with twist angles between neighboring layers in the same direction. We show here that flat bands exist in a variety of multilayers where the ratio between twist angles is close to coprime integers. We generalize previous analyses, and, using the chiral limit for interlayer coupling, give examples of many combinations of twist angles in stacks made up of three and four layers which lead to flat bands. The technique we use can be extended to systems with many layers. Our results suggest that flat bands can exist in graphene multilayers with angle disorder, that is, narrow samples of turbostatic graphite.
title Extended magic phase in twisted graphene multilayers
topic Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2305.18080