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Related papers: Heterostrain rules the flat-bands in magic-angle t…

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In recent experiments, superconductivity and correlated insulating states were observed in twisted bilayer graphene (TBG) with small magic angles, which highlights the importance of the flat bands near Fermi energy. However, the moir\'e…

Materials Science · Physics 2020-02-11 Jing-Yang You , Bo Gu , Gang Su

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 existence of Bloch flat bands provides an facile pathway to realize strongly correlated phenomena in materials. Using density-functional theory and tight-binding approach, we show that the flat bands can form in twisted bilayer of…

Materials Science · Physics 2020-03-04 Xing-Ju Zhao , Yang Yang , Dong-Bo Zhang , Su-Huai Wei

Flat electronic bands with tunable structures offer opportunities for the exploitation and manipulation of exotic interacting quantum states. Here, we present a controllable route to construct easily tunable flat bands in folded graphene,…

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…

We study the influence of strong spin-orbit interaction on the formation of flat bands in relaxed twisted bilayer WSe$_2$. Flat bands, well separated in energy, emerge at the band edges for twist angles ($\theta$) near 0$^{\circ}$ and…

Materials Science · Physics 2022-02-23 Sudipta Kundu , Mit H. Naik , H. R. Krishnamurthy , Manish Jain

We propose a tunable optical setup to engineer topologically nontrivial flat bands in twisted bilayer graphene under circularly polarized light. Using both analytical and numerical calculations, we demonstrate that nearly flat bands can be…

Strongly Correlated Electrons · Physics 2020-12-18 Yantao Li , H. A. Fertig , Babak Seradjeh

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

Van der Waals heterostructures obtained by artificially stacking two-dimensional crystals represent the frontier of material engineering, demonstrating properties superior to those of the starting materials. Fine control of the interlayer…

We implement a self-consistent Hartree-Fock approximation based on a microscopic model in real space, which allows us to consider the interplay between the Hubbard and the extended Coulomb interaction in twisted bilayer graphene at the…

Mesoscale and Nanoscale Physics · Physics 2021-09-15 J. Gonzalez , T. Stauber

We theoretically study the band structure and optical conductivity of twisted bilayer graphene (TBG) near the magic angle considering the effects of lattice relaxation. We show that the optical conductivity spectrum is characterized by a…

Mesoscale and Nanoscale Physics · Physics 2021-02-03 Lu Wen , Zhiqiang Li , Yan He

The low-energy bands of twisted bilayer graphene form Dirac cones with approximate electron-hole symmetry at small rotation angles. These crossings are protected by the emergent symmetries of moir\'e patterns, conferring a topological…

Mesoscale and Nanoscale Physics · Physics 2020-11-25 Hector Ochoa

A variety of exotic quantum phases of matter have been created by Van der Waals heterostructures. Moreover, these twisted heterostructures provide a feasible way of braiding correlation effect and nontrivial band topology together. Here,…

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

Twisted bilayer graphene (TBG) is a recently discovered two-dimensional superlattice structure which exhibits strongly-correlated quantum many-body physics, including strange metallic behavior and unconventional superconductivity. Most of…

Mesoscale and Nanoscale Physics · Physics 2024-04-22 Cunyuan Jiang , Matteo Baggioli , Qing-Dong Jiang

The bands of graphite are extremely sensitive to topological defects which modify the electronic structure. In this paper we found non-dispersive flat bands no farther than 10 meV of the Fermi energy in slightly twisted bilayer graphene as…

Mesoscale and Nanoscale Physics · Physics 2010-12-21 E. Suárez Morell , J. D. Correa , P. Vargas , M. Pacheco , Z. Barticevic

We study the zero-temperature many-body properties of twisted bilayer graphene with a twist angle equal to the so-called `first magic angle'. The system low-energy single-electron spectrum consists of four (eight, if spin label is…

Strongly Correlated Electrons · Physics 2019-07-30 A. O. Sboychakov , A. V. Rozhkov , A. L. Rakhmanov , Franco Nori

The chiral Hamiltonian for twisted graphene bilayers is written as a $2\times2$ matrix operator by a renormalization of the Hamiltonian that takes into account the particle-hole symmetry. This results in an effective Hamiltonian with an…

Mesoscale and Nanoscale Physics · Physics 2023-08-01 Gerardo G. Naumis , Leonardo A. Navarro-Labastida , Enrique Aguilar-Méndez , Abdiel Espinosa-Champo

The electronic properties of moir\'e heterostructures depend sensitively on the relative orientation between layers of the stack. For example, near-magic-angle twisted bilayer graphene (TBG) commonly shows superconductivity, yet a TBG…

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