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Breakthroughs in two-dimensional van der Waals heterostructures have revealed that twisting creates a moir\'e pattern that quenches the kinetic energy of electrons, allowing for exotic many-body states. We show that cold-atomic, trapped…

Strongly Correlated Electrons · Physics 2020-11-12 Yixing Fu , E. J. König , J. H. Wilson , Yang-Zhi Chou , J. H. Pixley

Magic-angle twisted bilayer graphene is the best studied physical platform featuring moire potential induced narrow bands with non-trivial topology and strong electronic correlations. Despite their significance, the Chern insulating states…

Mesoscale and Nanoscale Physics · Physics 2024-06-11 Xiaoyu Wang , Oskar Vafek

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

The chiral Hamiltonian for twisted graphene bilayers is analyzed in terms of its squared Hamiltonian which removes the particle-hole symmetry and thus one bipartite lattice, allowing to write the Hamiltonian in terms of a $2\times 2$…

Mesoscale and Nanoscale Physics · Physics 2022-04-13 Leonardo A. Navarro-Labastida , Abdiel Espinosa-Champo , Enrique Aguilar-Mendez , Gerardo G. Naumis

Using scanning probe microscopy and spectroscopy, we explore the spatial symmetry of the electronic wavefunctions of twisted bilayer graphene at the "magic angle" of 1.1 degrees. This small twist angle leads to a long wavelength moir\'e…

Mesoscale and Nanoscale Physics · Physics 2020-08-12 Zhiming Zhang , Rachel Myers , Kenji Watanabe , Takashi Taniguchi , Brian J. LeRoy

Motivated by recent Physical Review Letters of Wang-Liu and Ledwith-Vishwanath-Khalaf, we study Tarnopolsky-Kruchkov-Vishwanath chiral model of two sheets of $n$-layer Bernal stacked graphene twisted by a small angle using the framework…

Mathematical Physics · Physics 2023-11-16 Mengxuan Yang

The interest in the properties of edge states in Chern insulators and in $\mathbb{Z}_2$ topological insulator has increased rapidly in recent years. We present calculations on how to influence the transport properties of chiral and helical…

Mesoscale and Nanoscale Physics · Physics 2017-07-11 M. Malki , G. S. Uhrig

We investigate the effect of a magnetic field on the band structure of bilayer graphene with a magic twist angle of 1.08{\deg}. The coupling of a tight-binding model and the Peierls phase allows the calculation of the energy bands of…

Mesoscale and Nanoscale Physics · Physics 2024-05-20 Gaëlle Bigeard , Alessandro Cresti

We theoretically study the electronic structure of magic-angle twisted bilayer graphene with disordered moir\'e patterns. By using an extended continuum model incorporating non-uniform lattice distortion, we find that the local density of…

Mesoscale and Nanoscale Physics · Physics 2022-06-29 Naoto Nakatsuji , Mikito Koshino

Bilayer graphene twisted at the angle of about 1.1{\deg} better known as magic angle, exhibits ultra-flat moir\'e superlattice bands that are a source of highly-tunable, exotic quantum phenomena. Such phenomena, like superconductivity,…

Strongly Correlated Electrons · Physics 2024-11-05 Giovanna Feraco , Wissem Boubaker , Petra Rudolf , Antonija Grubišić-Čabo

Multilayer moir\'e materials can exhibit topological electronic features yet are inherently quasiperiodic -- leading to wave function interference whose Anderson-localizing tendency can be mitigated by topology. We consider a quasiperiodic…

Mesoscale and Nanoscale Physics · Physics 2025-01-22 Xinghai Zhang , Justin H. Wilson , Matthew S. Foster

We investigate twisted bilayer graphene near charge neutrality using a generalized Bistritzer-MacDonald continuum model, accounting for corrugation effects. The Fermi velocity vanishes for particular twist angles properly reproducing the…

Strongly Correlated Electrons · Physics 2022-09-07 Eric Brillaux , David Carpentier , Andrei A. Fedorenko , Lucile Savary

We present transport measurements of bilayer graphene with 1.38{\deg} interlayer twist and apparent additional alignment to its hexagonal boron nitride cladding. As with other devices with twist angles substantially larger than the magic…

We show that the electronic structure of the low-energy bands in the small angle-twisted bilayer graphene consists of a series of semi-metallic and topological phases. In particular we are able to prove, using an approximate low-energy…

Mesoscale and Nanoscale Physics · Physics 2019-07-24 Zhida Song , Zhijun Wang , Wujun Shi , Gang Li , Chen Fang , B. Andrei Bernevig

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…

Strongly Correlated Electrons · Physics 2024-03-20 D. C. W. Foo , Z. Zhan , Mohammed M. Al Ezzi , L. Peng , S. Adam , F. Guinea

Angle disorder is an intrinsic feature of twisted bilayer graphene and other moir\'e materials. Here, we discuss electron transport in twisted bilayer graphene in the presence of angle disorder. We compute the local density of states and…

Mesoscale and Nanoscale Physics · Physics 2021-09-08 Héctor Sainz-Cruz , Tommaso Cea , Pierre A. Pantaleón , Francisco Guinea

One of the most remarkable theoretical findings in magic angle twisted bilayer graphene (TBG) is the emergence of ferromagnetic Slater determinants as exact ground states for the interacting Hamiltonian at the chiral limit. This discovery…

Mathematical Physics · Physics 2025-06-02 Simon Becker , Lin Lin , Kevin D. Stubbs

We provide a mathematical account of the recent Physical Reviews Letter by Tarnopolsky--Kruchkov--Vishwanath. The new contributions are a spectral characterization of magic angles, its accurate numerical implementation and an exponential…

Mathematical Physics · Physics 2022-05-18 Simon Becker , Mark Embree , Jens Wittsten , Maciej Zworski

Recent experiments on bilayer graphene twisted near the magic angle have observed spontaneous integer quantum Hall states in the presence of an aligned hexagonal boron nitride (hBN) substrate. These states arise from valley ferromagnetism,…

Strongly Correlated Electrons · Physics 2020-06-18 Patrick J. Ledwith , Grigory Tarnopolsky , Eslam Khalaf , Ashvin Vishwanath

The emergence of flat bands in twisted bilayer graphene at the magic angle can be understood in terms of a vanishing Fermi velocity of the Dirac cone. This is associated with van Hove singularities approaching the Fermi energy and becoming…

Strongly Correlated Electrons · Physics 2023-06-05 A. S. Shankar , D. O. Oriekhov , Andrew K. Mitchell , L. Fritz