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Divergent density of states offers the unique opportunity to explore a wide variety of correlated electron physics. In the thinnest limit, this has been predicted and verified in the ultra-flat bands of magic-angle twisted bilayer graphene,…

Mesoscale and Nanoscale Physics · Physics 2022-08-15 Anna M. Seiler , Fabian R. Geisenhof , Felix Winterer , Kenji Watanabe , Takashi Taniguchi , Tianyi Xu , Fan Zhang , R. Thomas Weitz

We show that topology of the low-energy band structure in bilayer graphene critically depends on mechanical deformations of the crystal which may easily develop in suspended graphene flakes. We describe the Lifshitz transition that takes…

Mesoscale and Nanoscale Physics · Physics 2011-07-19 Marcin Mucha-Kruczynski , Igor L. Aleiner , Vladimir I. Fal'ko

Recent transport studies have demonstrated the great potential of twisted monolayer-bilayer graphene (tMBG) as a new platform to host moir\'e flat bands with a higher tunability than twisted bilayer graphene (tBG). However, a direct…

Mesoscale and Nanoscale Physics · Physics 2024-01-10 Ling-Hui Tong , Qingjun Tong , Li-Zhen Yang , Yue-Ying Zhou , Qilong Wu , Yuan Tian , Li Zhang , Lijie Zhang , Zhihui Qin , Long-Jing Yin

It is widely known that the twisted bilayer graphene (TBG) shows flat bands at magic angles, which can be well described by the effective continuum model derived by Bistritzer and MacDonald (BM). We propose in this paper a similar twisted…

Mesoscale and Nanoscale Physics · Physics 2022-04-22 Y. Soeda , K. Asaga , T. Fukui

We show that the flat bands in the chiral model of magic-angle twisted bilayer graphene remain exactly flat in the presence of a perpendicular magnetic field. This is shown by an exact mapping between the model and the lowest Landau level…

Strongly Correlated Electrons · Physics 2021-09-29 Yarden Sheffer , Ady Stern

Twisted bilayer graphene is a rich condensed matter system, which allows one to tune energy scales and electronic correlations. The low-energy physics of the resulting moir\'e structure can be mathematically described in terms of a…

Mesoscale and Nanoscale Physics · Physics 2024-06-21 Alireza Parhizkar , Victor Galitski

Very recently, twisted graphene bilayer (TGB) around the first magic angle 1.1{\deg} has attracted much attention for the realization of exotic quantum states, such as correlated insulator behavior and unconventional superconductivity. Here…

Materials Science · Physics 2019-04-10 Jia-Bin Qiao , Long-Jing Yin , Lin He

The electronic bands of twisted bilayer graphene (TBLG) with a large-period moir\'e superlattice fracture to form narrow Bloch minibands that are spectrally isolated by forbidden energy gaps from remote dispersive bands. When these gaps are…

Mesoscale and Nanoscale Physics · Physics 2020-10-28 Vo Tien Phong , E. J. Mele

Recently twisted bilayer graphene (t-BLG) emerges as a new strongly correlated physical platform near a magic twist angle, which hosts many exciting phenomena such as the Mott-like insulating phases, unconventional superconducting behavior…

Our theoretical study unfolds the topological phase transitions (within bands of the Moir\'e super-lattice) in small angle twisted double bilayer graphene (tDBLG) under the influence of external gate voltage and intrinsic spin-orbit…

Mesoscale and Nanoscale Physics · Physics 2025-02-05 Kamalesh Bera , Priyanka Mohan , Arijit Saha

Small-twist-angle bilayer graphene supports strongly correlated insulating states and superconductivity. Twisted few-layer graphene systems are likely to open up new directions for strong correlation physics in moir\'e superlattices. We…

Materials Science · Physics 2019-07-30 Xiao Li , Fengcheng Wu , Allan H. MacDonald

The structural and electronic properties of twisted bilayer graphene are investigated from first principles and tight binding approach as a function of the twist angle (ranging from the first "magic" angle $\theta=1.08^\circ$ to…

Materials Science · Physics 2020-10-28 G. Cantele , D. Alfè , F. Conte , V. Cataudella , D. Ninno , P. Lucignano

Twisted bilayer graphene has been argued theoretically to host exceptionally flat bands when the angle between the two layers falls within a magic range near 1.1$^\circ$. This is now strongly supported by experiment, which furthermore…

Strongly Correlated Electrons · Physics 2019-07-24 Kasra Hejazi , Chunxiao Liu , Leon Balents

We present a theoretical investigation of the magnetic properties exhibited by twisted bilayer graphene (TBG) systems with small twist angles, where the appearance of flat minibands strongly enhances electron-electron interaction effects.…

Mesoscale and Nanoscale Physics · Physics 2025-04-08 Kevin J. U. Vidarte , Felipe Pérez Riffo , Eric Suárez Morell , Caio Lewenkopf

Magic-angle twisted bilayer graphene has recently become a thriving material platform realizing correlated electron phenomena taking place within its topological flat bands. Several numerical and analytical methods have been applied to…

Strongly Correlated Electrons · Physics 2021-09-17 Bin-Bin Chen , Yuan Da Liao , Ziyu Chen , Oskar Vafek , Jian Kang , Wei Li , Zi Yang Meng

Magic-angle twisted bilayer graphene (MATBG) is notable as a highly tunable platform for investigating strongly correlated phenomena such as high-$T_c$ superconductivity and quantum spin liquids, due to easy control of doping level through…

Mesoscale and Nanoscale Physics · Physics 2020-06-04 Xiao Chen , Shuanglong Liu , James N Fry , Hai-Ping Cheng

Graphene, a one-layer honeycomb lattice of carbon atoms, exhibits unconventional phenomena and attracts much interest since its discovery. Recently, an unexpected Mott-like insulator state induced by moir\'e pattern and a superconducting…

Mesoscale and Nanoscale Physics · Physics 2019-11-22 Yao Wang , Yi-Jun Chang , Jun Gao , Yong-Heng Lu , Zhi-Qiang Jiao , Fang-Wei Ye , Xian-Min Jin

The recent discovery of correlated insulator states and superconductivity in magic-angle twisted bilayer graphene has paved the way to the experimental investigation of electronic correlations in tunable flat band systems realized in…

Magic-angle twisted bilayer graphene (MA-TBG) exhibits intriguing quantum phase transitions triggered by enhanced electron-electron interactions when its flat-bands are partially filled. However, the phases themselves and their connection…

Mesoscale and Nanoscale Physics · Physics 2021-04-14 Shuang Wu , Zhenyuan Zhang , K. Watanabe , T. Taniguchi , Eva Y. Andrei

In this work, we study an interacting tight-binding model of magic-angle twisted bilayer graphene (MATBG), with a twist angle of $1.05^\circ$. We derive effective theories based on a mean-field normal state at charge neutrality, thereby…

Strongly Correlated Electrons · Physics 2025-05-27 Miguel Sánchez Sánchez , José González , Tobias Stauber