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The electronic properties of junctions defined electrostatically on twisted bilayer graphene can be addressed theoretically using lattice models. Recent works have introduced minimal local orbital models to describe twisted bilayer graphene…

Mesoscale and Nanoscale Physics · Physics 2021-08-11 M. Alvarado , A. Levy Yeyati

The recent experimental studies of twisted bilayer graphene (TBG) raise a fundamental question: how do we understand Mott localization in a topological band? In this work, we offer a new perspective of Mott physics, which can be generalized…

Strongly Correlated Electrons · Physics 2025-05-20 Jing-Yu Zhao , Boran Zhou , Ya-Hui Zhang

Superlattices from twisted graphene mono- and bi-layer systems give rise to on-demand many-body states such as Mott insulators and unconventional superconductors. These phenomena are ascribed to a combination of flat bands and strong…

The understanding of strongly-correlated materials, and in particular unconventional superconductors, has puzzled physicists for decades. Such difficulties have stimulated new research paradigms, such as ultra-cold atom lattices for…

Mesoscale and Nanoscale Physics · Physics 2018-05-22 Yuan Cao , Valla Fatemi , Shiang Fang , Kenji Watanabe , Takashi Taniguchi , Efthimios Kaxiras , Pablo Jarillo-Herrero

The moir\'e superlattice formed by ABC stacked trilayer graphene aligned with a hexagonal boron nitride substrate (TG/h-BN) provides an interesting system where both the bandwidth and the topology can be tuned by an applied perpendicular…

Strongly Correlated Electrons · Physics 2019-06-05 Ya-Hui Zhang , T. Senthil

Magic-Angle Twisted Bilayer Graphene shows a wide range of correlated phases which are electrostatically tunable. Despite a growing knowledge of the material, there is yet no consensus on the microscopic mechanisms driving its…

Moir\'e transition metal dichalcogenide (TMD) materials provide an ideal playground for studying the combined interplay of strong interactions and band-topology over a range of electronic fillings. Here we investigate the panoply of…

Strongly Correlated Electrons · Physics 2024-11-22 Juan Felipe Mendez-Valderrama , Sunghoon Kim , Debanjan Chowdhury

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…

A purely electronic mechanism is proposed for the unconventional superconductivity recently observed in twisted bilayer graphene (tBG) close to the magic angle. Using the Migdal-Eliashberg framework on a one parameter effective lattice…

Mesoscale and Nanoscale Physics · Physics 2024-02-19 Gargee Sharma , Maxim Trushin , Oleg P. Sushkov , Giovanni Vignale , Shaffique Adam

We study ferromagnetism and its stability in twisted bilayer graphene. We work with a Hubbard-like interaction that corresponds to the screened Coulomb interaction in a well-defined limit where the Thomas-Fermi screening length…

Mesoscale and Nanoscale Physics · Physics 2021-01-04 Yahya Alavirad , Jay D. Sau

In single sheets of graphene, vacancy-induced states have been shown to host an effective spin-1/2 hole that can be Kondo-screened at low temperatures. Here, we show how these vacancy-induced impurity states survive in twisted bilayer…

Strongly Correlated Electrons · Physics 2024-10-07 Yueqing Chang , Jinjing Yi , Ang-Kun Wu , Fabian B. Kugler , Eva Y. Andrei , David Vanderbilt , Gabriel Kotliar , J. H. Pixley

Magic-angle twisted bilayer graphene (MATBG) hosts a number of correlated states of matter that can be tuned by electrostatic doping. Superconductivity has drawn considerable attention and the mechanism behind it is a topic of active…

Kondo physics and heavy-fermion behavior have been predicted and observed in moir\'e materials. The electric tunability of moir\'e materials allows an in-situ study of Kondo lattices' phase diagrams, which is not possible with their…

Mesoscale and Nanoscale Physics · Physics 2025-07-23 Antonio L. R. Manesco

Fractional quantum anomalous Hall effects realized in twisted bilayer MoTe$_2$ and multilayer-graphene-based moir\'e heterostructures have captured a tremendous growth of interest. In this work, we propose that rhombohedral multilayer…

Mesoscale and Nanoscale Physics · Physics 2025-03-17 Yanran Shi , Bo Xie , Fengfan Ren , Xinyu Cai , Zhongqing Guo , Qiao Li , Xin Lu , Nicolas Regnault , Zhongkai Liu , Jianpeng Liu

By tuning the angle between graphene layers to specific "magic angles" the lowest energy bands of twisted bilayer graphene (TBLG) can be made flat. The flat nature of the bands favors the formation of collective ground states and, in…

Superconductivity · Physics 2019-12-09 Xiang Hu , Timo Hyart , Dmitry I. Pikulin , Enrico Rossi

The emergence of flat electronic bands and of the recently discovered strongly correlated and superconducting phases in twisted bilayer graphene crucially depends on the interlayer twist angle upon approaching the magic angle $\theta_M…

The double exchange model with on-site Coulomb repulsion is considered. Schwinger-bosons representation of the localized spins is used and two spin-singlet Fermion operators are introduced. In terms of the new Fermi fields the on-site…

Strongly Correlated Electrons · Physics 2015-06-25 Naoum Karchev , Vasil Michev

We compute the phase diagram of twisted bilayer graphene near the magic angle where the occurrence of flat bands enhances the effects of electron-electron interactions and thus unleashes strongly-correlated phenomena. Most importantly, we…

Strongly Correlated Electrons · Physics 2018-12-26 Dante M. Kennes , Johannes Lischner , Christoph Karrasch

At partial fillings of its flat electronic bands, magic-angle twisted bilayer graphene (MATBG) hosts a rich variety of competing correlated phases that show sample to sample variations. Divergent phase diagrams in MATBG are often attributed…

Mesoscale and Nanoscale Physics · Physics 2023-07-12 Dillon Wong , Kevin P. Nuckolls , Myungchul Oh , Ryan L. Lee , Kenji Watanabe , Takashi Taniguchi , Ali Yazdani

Magic-angle twisted bilayer graphene (tBLG) has been studied extensively owing to its wealth of symmetry-broken phases, correlated Chern insulators, orbital magnetism, and superconductivity. In particular, the anomalous Hall effect (AHE)…

Mesoscale and Nanoscale Physics · Physics 2022-12-13 Chun-Chih Tseng , Xuetao Ma , Zhaoyu Liu , Kenji Watanabe , Takashi Taniguchi , Jiun-Haw Chu , Matthew Yankowitz