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We experimentally investigate the band structures of chirally twisted triple bilayer graphene. The new kind of moir\'e structure, formed by three pieces of helically stacked Bernal bilayer graphene, has flat bands at charge neutral point…

Mesoscale and Nanoscale Physics · Physics 2025-01-14 Wenlu Lin , Wenxuan Wang , Shimin Cao , Miao Liang , Lili Zhao , Kenji Watanabe , Takashi Taniguchi , Jinhua Gao , Jianhao Chen , Xiaobo Lu , Yang Liu

Twisted bilayer graphene (TBG) hosts nearly flat bands with narrow bandwidths of a few meV at certain {\em magic} twist angles. Here we show that in twisted gapped Dirac material bilayers, or massive twisted bilayer graphenes (MTBG),…

Mesoscale and Nanoscale Physics · Physics 2020-03-18 Srivani Javvaji , Jinhua Sun , Jeil Jung

We discuss a number of illuminating results for tight binding models supporting a band with variable Chern number, and illustrate them explicitly for a simple class of two-banded models. First, for models with a fixed number of bands, we…

Strongly Correlated Electrons · Physics 2014-10-21 Masafumi Udagawa , Emil J. Bergholtz

We explain the appearance of magic angles and fractional Chern insulators in twisted K-valley homobilayer transition metal dichalcogenides by mapping their continuum model to a Landau level problem. Our approach relies on an adiabatic…

Strongly Correlated Electrons · Physics 2024-06-21 Nicolás Morales-Durán , Nemin Wei , Jingtian Shi , Allan H. MacDonald

Fractional Chern insulators arise in topologically nontrivial flat bands, characterized by an integer Chern number C that corresponds to the number of dissipationless edge states in the non-interacting regime. Higher Chern numbers can…

Strongly Correlated Electrons · Physics 2026-01-29 Ying-Xing Ding , Wen-Tong Li , Li-Min Zhang , Yu-Biao Wu , Duanlu Zhou , Lin Zhuang , Wu-Ming Liu

We propose an effective lattice model for the moir\'e structure of the twisted bilayer dice lattice. In the chiral limit, we find that there are flat bands at the zero-energy level at any twist angle besides the magic ones and these flat…

Mesoscale and Nanoscale Physics · Physics 2024-04-25 Di Ma , Yu-Ge Chen , Yue Yu , Xi Luo

We study the electronic band structure and the topological property of the twisted double bilayer graphene, or a pair of AB-stacked bilayer graphenes rotationally stacked on top of each other. We consider two different arrangements, AB-AB…

Mesoscale and Nanoscale Physics · Physics 2019-06-10 Mikito Koshino

Bernal-stacked bilayer graphene modulated by a superlattice potential is a highly tunable system predicted to realize isolated topological flat bands. In this work we calculate the band structure and quantum geometry of bilayer graphene…

Mesoscale and Nanoscale Physics · Physics 2025-05-12 Dathan Ault-McCoy , M. Nabil Y. Lhachemi , Aaron Dunbrack , Sayed Ali Akbar Ghorashi , Jennifer Cano

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

Twisted bilayer graphene exhibits isolated, relatively flat electronic bands near charge neutrality when the interlayer rotation is tuned to specific magic angles. These small misalignments, typically below 1.1{\deg}, result in long-period…

Mesoscale and Nanoscale Physics · Physics 2026-03-26 Antonio Palamara , Michele Pisarra , Antonello Sindona

We consider a configuration of three stacked graphene monolayers with commensurate twist angles $\theta_{12}/\theta_{23}=p/q$, where $p$ and $q$ are coprime integers with $0<p<|q|$ and $q$ can be positive or negative. We study this system…

Strongly Correlated Electrons · Physics 2023-06-14 Fedor K. Popov , Grigory Tarnopolsky

Twisted bilayer graphenes with magical angle exhibit strongly correlated electronic properties because of the isolated flat band at the Fermi level. We studied the twisted bilayer graphene with substrates on both layers. The substrate…

Mesoscale and Nanoscale Physics · Physics 2019-07-30 Ma Luo

Twisted bilayer graphene with a twist angle of around 1.1{\deg} features a pair of isolated flat electronic bands and forms a strongly correlated electronic platform. Here, we use scanning tunneling microscopy to probe local properties of…

We study the electronic structures and topological properties of $(M+N)$-layer twisted graphene systems. We consider the generic situation that $N$-layer graphene is placed on top of the other $M$-layer graphene, and is twisted with respect…

Mesoscale and Nanoscale Physics · Physics 2019-08-14 Jianpeng Liu , Zhen Ma , Jinhua Gao , Xi Dai

We study flat bands and their topology in 2D materials with quadratic band crossing points (QBCPs) under periodic strain. In contrast to Dirac points in graphene, where strain acts as a vector potential, strain for QBCPs serves as a…

Mesoscale and Nanoscale Physics · Physics 2023-05-30 Xiaohan Wan , Siddhartha Sarkar , Shi-Zeng Lin , Kai Sun

Twisted bilayer graphene (TBG) hosts a rich landscape of electronic phases arising from the interplay between strong electron-electron interactions and nontrivial band topology. While the flat bands near zero energy are central to many…

Mesoscale and Nanoscale Physics · Physics 2026-02-16 Leonardo A. Navarro-Labastida , Pierre A. Pantaleon , Francisco Guinea , Gerardo G. Naumis

Stacked graphene multilayers with a small relative twist angle between each of the layers have been found to host flat bands at a series of magic angles. We consider the effect that Dirac point asymmetry between the layers, and in…

Mesoscale and Nanoscale Physics · Physics 2024-12-31 Adam Eaton , Yantao Li , Herbert Fertig , Babak Seradjeh

Twist bilayer graphenes with magical angle have nearly flat band, which become strongly correlated electron systems. Herein, we propose another system based on strained bilayer graphene that have flat band at the intrinsic Fermi level. The…

Mesoscale and Nanoscale Physics · Physics 2019-01-28 Ma Luo

Here we present a theory of mirror-symmetric magic angle twisted trilayer graphene. The electronic properties are described by a Hubbard model with long range tunneling matrix elements. The electronic properties are obtained by solving the…

Mesoscale and Nanoscale Physics · Physics 2026-05-13 Alina Wania Rodrigues , Maciej Bieniek , Daniel Miravet , Pawel Hawrylak

We demonstrate that flat bands with local Berry curvature arise naturally in chiral (ABC) multilayer graphene placed on a boron nitride (BN) substrate. The degree of flatness can be tuned by varying the number of graphene layers N. For N =…

Mesoscale and Nanoscale Physics · Physics 2013-07-24 Akshay Kumar , Rahul Nandkishore