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The novel physics of twisted bilayer graphene has motivated extensive studies of magic-angle flat bands hosted by moir\'e structures in electronic, photonic and acoustic systems. On the other hand, bound states in the continuum (BICs) have…

Optics · Physics 2022-07-13 Lei Huang , Weixuan Zhang , Xiangdong Zhang

We show that the insulating states of magic-angle twisted bilayer graphene support a series of collective modes corresponding to local particle-hole excitations on triangular lattice sites. Our theory is based on a continuum model of the…

Strongly Correlated Electrons · Physics 2021-07-09 Ajesh Kumar , Ming Xie , A. H. MacDonald

Flatbands with extremely narrow bandwidths on the order of a few mili-electron volts can appear in twisted multilayer graphene systems for appropriate system parameters. Here we investigate the electronic structure of a twisted bi-bilayer…

Mesoscale and Nanoscale Physics · Physics 2019-06-24 Narasimha Raju Chebrolu , Bheema Lingam Chittari , Jeil Jung

We investigate the electronic spectra and quantum Hall effect in twisted bilayer graphenes with various rotation angles under magnetic fields, using a model rigorously including the interlayer interaction. We describe the spectral evolution…

Mesoscale and Nanoscale Physics · Physics 2012-05-31 Pilkyung Moon , Mikito Koshino

We build an effective medium theory for two-dimensional photonic crystals comprising a rectangular lattice of dielectric cylinders with the incident electric field polarized along the axis of the cylinders. In particular, we discuss the…

Optics · Physics 2016-03-23 Meng Xiao , Xueqin Huang , Anan Fang , C. T. Chan

We present a theoretical study of the intrinsic plasmonic properties of twisted bilayer graphene (TBG) as a function of the twist angle $\theta$ (and other microscopic parameters such as temperature and filling factor). Our calculations,…

Mesoscale and Nanoscale Physics · Physics 2024-09-06 Lorenzo Cavicchi , Iacopo Torre , Pablo Jarillo-Herrero , Frank H. L. Koppens , Marco Polini

Two-dimensional atomic crystals can radically change their properties in response to external influences such as substrate orientation or strain, resulting in essentially new materials in terms of the electronic structure. A striking…

We study the correlated insulating phases of twisted bilayer graphene (TBG) in the absence of lattice strain at integer filling $\nu=\pm3$. Using the self-consistent Hartree-Fock method on a particle-hole symmetric model and allowing…

Strongly Correlated Electrons · Physics 2023-03-01 Fang Xie , Jian Kang , B. Andrei Bernevig , Oskar Vafek , Nicolas Regnault

The creation of moir\'e superlattices in twisted bilayers of two-dimensional crystals has been utilised to engineer quantum material properties in graphene and transition metal dichalcogenide (TMD) semiconductors. Here, we examine the…

Mesoscale and Nanoscale Physics · Physics 2024-05-27 J. G. McHugh , V. V. Enaldiev , V. I. Fal'ko

For twisted bilayer graphene close to magic angle, we show that the effects of lattice relaxation and the Hartree interaction both become simultaneously important. Including both effects in a continuum theory reveals a Lifshitz transition…

Strongly Correlated Electrons · Physics 2024-04-30 Mohammed M. Al Ezzi , Liangtao Peng , Zhengyu Liu , Jonah Huang Zi Chao , Gayani N. Pallewela , Darryl Foo , Shaffique Adam

We construct a minimal theory describing the optical activity of a thin sheet of a twisted material, the simplest example of which is twisted bilayer graphene. We introduce the notion of "twisted electrical conductivity", which parametrizes…

Mesoscale and Nanoscale Physics · Physics 2020-08-10 Dung Xuan Nguyen , Dam Thanh Son

Magic angle twisted bilayer graphene (MATBG) hosts narrow moir\'e bands with meV-scale energy splittings, making its correlated phases sensitive to both material parameters and modeling choices in low-energy downfolding. We develop an ab…

Strongly Correlated Electrons · Physics 2026-03-12 Raehyun Kim , Woochang Kim , Kevin D. Stubbs , Steven G. Louie , Lin Lin

We present efficient angle-dependent low-energy Hamiltonians to describe the properties of the twisted bilayer graphene (tBLG) heterostructure, based on {\it ab initio} calculations of mechanical relxation and electronic structure. The…

Mesoscale and Nanoscale Physics · Physics 2019-08-02 Shiang Fang , Stephen Carr , Ziyan Zhu , Daniel Massatt , Efthimios Kaxiras

We investigate the electronic density redistribution of rotated bilayer graphene under a perpendicular electric field, showing that the layers are actually coupled even for large angles. This layer-layer coupling is evidenced by the charge…

Mesoscale and Nanoscale Physics · Physics 2012-03-26 E. Suárez Morell , P. Vargas , L. Chico , L. Brey

We have studied how a generic bilayer kagome lattice behave upon layer rotation. We employed a Tight Binding model with one orbital per site and found (i) for low rotational angles, and at low energies, the same flat bands structure like in…

Mesoscale and Nanoscale Physics · Physics 2019-10-28 F. Crasto de Lima , R. H. Miwa , E. Suárez Morell

We investigate the electronic structure and the optical absorption onset of close-to-30\degree twisted hexagonal boron nitride bilayers. Our study is carried out with a purposely developed tight-binding model validated against DFT…

Materials Science · Physics 2024-05-22 Lorenzo Sponza , Van Binh Vu , Elisa Serrano Richaud , Hakim Amara , Sylvain Latil

This work theoretically explores how to emulate twisted double bilayer graphene with ultracold atoms in multiorbital optical lattices. In particular, the quadratic band touching of Bernal stacked bilayer graphene is emulated using a square…

Quantum Gases · Physics 2021-12-28 Junhyun Lee , J. H. Pixley

Recent studies on the interplay between band topology and layer degree of freedom provide an effective way to realize exotic topological phases. Here we systematically study the $C_6$- and $C_3$-symmetric higher-order topological phases in…

Mesoscale and Nanoscale Physics · Physics 2024-01-17 Xiao-Yu Liu , Yang Liu , Zhan Xiong , Hai-Xiao Wang , Jian-Hua Jiang

Twistronics, harnessing interlayer rotation to tailor electronic states in van der Waals materials, has predominantly focused on small-angle regime. Here, we unveil the pivotal role of intervalley Umklapp scattering in large-angle twisted…

Mesoscale and Nanoscale Physics · Physics 2025-12-16 Juncheng Li , Cong Chen , Wang Yao

Here we present a theoretical analysis (applicable to all twist angles of TBG) of band dispersion and density of states in TBG relating evolution of flat band and Van-Hove singularities with evolution of interlayer coupling in TBG. A simple…

Mesoscale and Nanoscale Physics · Physics 2024-08-09 Veerpal , B. R. K. Nanda , Ajay