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Monolayer graphene placed with a twist on top of AB-stacked bilayer graphene hosts topological flat bands in a wide range of twist angles. The dispersion of these bands and gaps between them can be efficiently controlled by a perpendicular…

Strongly Correlated Electrons · Physics 2020-08-05 Louk Rademaker , Ivan Protopopov , Dmitry Abanin

A number of moir\'e graphene systems have nearly flat topological bands where electron motion is strongly correlated. Though microscopically these systems are only quasiperiodic, they can typically be treated as translation invariant to an…

Mesoscale and Nanoscale Physics · Physics 2021-03-10 Dan Mao , T. Senthil

Magic-angle twisted bilayer graphene (TBG) has attracted significant interest recently due to the discoveries of diverse correlated and topological states in this system. Despite the extensive research on the electron-electron interaction…

Mesoscale and Nanoscale Physics · Physics 2022-10-13 Xiaoqian Liu , Ran Peng , Zhaoru Sun , Jianpeng Liu

When two monolayers of graphene are stacked with a small relative twist angle, the resulting band structure exhibits a remarkably flat pair of bands at a sequence of 'magic angles' where correlation effects can induce a host of exotic…

Strongly Correlated Electrons · Physics 2019-08-14 Eslam Khalaf , Alex J. Kruchkov , Grigory Tarnopolsky , Ashvin Vishwanath

Twisting two layers into a magic angle (MA) of ~1.1{\deg} is found essential to create low energy flat bands and the resulting correlated insulating, superconducting, and magnetic phases in twisted bilayer graphene (TBG). While most of…

We show that the twisted graphene bilayer can reveal unusual topological properties at low energies, as a consequence of a Dirac-point splitting. These features rely on a symmetry analysis of the electron hopping between the two layers of…

Mesoscale and Nanoscale Physics · Physics 2011-07-21 R. de Gail , M. O. Goerbig , F. Guinea , G. Montambaux , A. H. Castro Neto

A remarkable feature of the band structure of bilayer graphene at small twist angle is the appearance of isolated bands near neutrality, whose bandwidth can be reduced at certain magic angles (eg. $\theta\sim 1.05^\circ$). In this regime,…

Strongly Correlated Electrons · Physics 2018-08-30 Liujun Zou , Hoi Chun Po , Ashvin Vishwanath , T. Senthil

We build symmetry adapted maximally localized Wannier states, and construct the low energy tight binding model for the four narrow bands of the twisted bilayer graphene. We do so when the twist angle is commensurate, near the `magic' value,…

Strongly Correlated Electrons · Physics 2018-10-02 Jian Kang , Oskar Vafek

Twisted bilayer graphene (TBG) has been experimentally observed to exhibit almost flat bands when the twisting occurs at certain magic angles. In this letter, we report new results on the continuum model of twisted bilayer graphene and its…

Strongly Correlated Electrons · Physics 2021-04-21 Simon Becker , Mark Embree , Jens Wittsten , Maciej Zworski

We investigate magnetic instabilities in charge-neutral twisted bilayer graphene close to so-called "magic angles" using a combination of real-space Hartree-Fock and dynamical mean-field theories. In view of the large size of the unit cell…

Strongly Correlated Electrons · Physics 2021-12-08 Javad Vahedi , Robert Peters , Ahmed Missaoui , Andreas Honecker , Guy Trambly de Laissardière

'Magic'-angle twisted bilayer graphene has received a lot of interest due to its flat bands with potentially non-trivial topology that lead to intricate correlated phases. A spectrum with flat bands, however, does not require a twist…

Mesoscale and Nanoscale Physics · Physics 2021-07-07 Anastasiia Skurativska , Stepan S. Tsirkin , Fabian D Natterer , Titus Neupert , Mark H Fischer

Magic angle twisted bilayer graphene has emerged as a powerful platform for studying strongly correlated electron physics, owing to its almost dispersionless low-energy bands and the ability to tune the band filling by electrostatic gating.…

Mesoscale and Nanoscale Physics · Physics 2021-07-21 Nikhil Tilak , Xinyuan Lai , Shuang Wu , Zhenyuan Zhang , Mingyu Xu , Raquel de Almeida Ribeiro , Paul C Canfield , Eva Y. Andrei

The rich phenomenology of twisted bilayer graphene (TBG) near the magic angle is believed to arise from electron correlations in topological flat bands. An unbiased approach to this problem is highly desirable, but also particularly…

Strongly Correlated Electrons · Physics 2021-09-28 Johannes S. Hofmann , Eslam Khalaf , Ashvin Vishwanath , Erez Berg , Jong Yeon Lee

We analyze the electronic structure of twisted bilayer graphene (TBG) nanoribbons close to the magic angle. We describe a transition from an incomplete to a complete moir\'e structure. By considering zigzag and armchair edge terminations,…

Mesoscale and Nanoscale Physics · Physics 2023-09-14 Elias Andrade , Pierre A. Pantaleón , Francisco Guinea , Gerardo G. Naumis

The interplay of twist and strain in bilayer graphene enables the formation of moir\'e patterns and narrow bands that host correlated and topological phases. While magic-angle twisted bilayer graphene has been widely studied, strain…

Mesoscale and Nanoscale Physics · Physics 2026-03-10 Federico Escudero , Dong Wang , Pierre A. Pantaleón , Shengjun Yuan , Francisco Guinea , Zhen Zhan

We study the atomic structure of twisted bilayer graphene, with very small mismatch angles ($\theta \sim 0.28^0$), a topic of intense recent interest. We use simulations, in which we combine a recently presented semi-empirical potential for…

Materials Science · Physics 2016-11-15 Sandeep K. Jain , Vladimir Juricic , Gerard T. Barkema

Electronic correlations in two-dimensional materials play a crucial role in stabilising emergent phases of matter. The realisation of correlation-driven phenomena in graphene has remained a longstanding goal, primarily due to the absence of…

Mesoscale and Nanoscale Physics · Physics 2023-09-19 Saisab Bhowmik , Arindam Ghosh , U. Chandni

The salient property of the electronic band structure of twisted bilayer graphene (TBG), at the so-called magic angle (MA), is the emergence of flat bands around the charge neutrality point. These bands are associated with the observed…

Mesoscale and Nanoscale Physics · Physics 2023-09-04 Sonia Haddad , Takeo Kato , Jihang Zhu , Lassaad Mandhour

According to electronic structure theory, bilayer graphene is expected to have anomalous electronic properties when it has long-period moir\'e patterns produced by small misalignments between its individual layer honeycomb lattices. We have…

Twisted bilayer systems with discrete magic angles, such as twisted bilayer graphene featuring moir\'{e} superlattices, provide a versatile platform for exploring novel physical properties. Here, we discover a class of superflat bands in…

Optics · Physics 2022-05-31 Hongfei Wang , Shaojie Ma , Shuang Zhang , Dangyuan Lei