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We revisit the localized Wannier state description of the twisted bilayer graphene, focusing on the chiral limit. We provide a simple method for constructing such 2D exponentially localized -- yet valley polarized -- Wannier states,…

Strongly Correlated Electrons · Physics 2021-09-02 Oskar Vafek , Jian Kang

We review analytical and numerical studies of correlated insulating states in twisted bilayer graphene, focusing on real-space lattice models constructions and their unbiased quantum many-body solutions. We show that by constructing…

Strongly Correlated Electrons · Physics 2021-01-12 Yuan Da Liao , Xiao Yan Xu , Zi Yang Meng , Jian Kang

Twisted bilayer graphene (TBLG) has emerged as an important platform for studying correlated phenomena, including unconventional superconductivity, in two-dimensional systems. The complexity of the atomic-scale structures in TBLG has made…

Strongly Correlated Electrons · Physics 2019-11-07 Stephen Carr , Shiang Fang , Hoi Chun Po , Ashvin Vishwanath , Efthimios Kaxiras

We develop an effective extended Hubbard model to describe the low-energy electronic properties of the twisted bilayer graphene. By using the Bloch states in the effective continuum model and with the aid of the maximally localized…

Mesoscale and Nanoscale Physics · Physics 2018-10-03 Mikito Koshino , Noah F. Q. Yuan , Takashi Koretsune , Masayuki Ochi , Kazuhiko Kuroki , Liang Fu

Monolayer graphene placed with a twist on top of AB-stacked bilayer graphene hosts topological flat bands in a wide range of twist angles. The dispersion of these bands and gaps between them can be efficiently controlled by a perpendicular…

Strongly Correlated Electrons · Physics 2020-08-05 Louk Rademaker , Ivan Protopopov , Dmitry Abanin

The newly realized twisted graphene systems such as twisted bilayer graphene (TBG), twisted double bilayer graphene (TDBG), and twisted trilayer graphene (TTG) have attracted widespread theoretical attention. Therefore, a simple and…

Mesoscale and Nanoscale Physics · Physics 2021-08-18 Jin Cao , Maoyuan Wang , Cheng-Cheng Liu , Yugui Yao

Bands with non-trivial topological indices have a topological obstruction preventing them from being represented by exponentially localized Wannier states. Here, we propose a procedure to construct exponentially localized Wannier functions…

Mesoscale and Nanoscale Physics · Physics 2025-05-29 Trey Cole , David Vanderbilt

We introduce an approach to derive realistic Coulomb interaction terms in free standing layered materials and vertical heterostructures from ab-initio modelling of the corresponding bulk materials. To this end, we establish a combination of…

Materials Science · Physics 2015-08-12 M. Rösner , E. Şaşıoğlu , C. Friedrich , S. Blügel , T. O. Wehling

One- and two-dimensional bilayer systems are examples of ultra-tunable quantum materials that are considered as the basis for the new generation of electronic and photonic devices. Here we develop a general theory of the electron band…

Mesoscale and Nanoscale Physics · Physics 2022-06-22 D. V. Chalin , D. I. Levshov , A. E. Myasnikova , S. B. Rochal

The recently introduced classification of two-dimensional insulators in terms of topological crystalline invariants has been applied so far to "obstructed" atomic insulators characterized by a mismatch between the centers of the electronic…

We argue that various kinds of topological insulators (TIs) can be insightfully characterized by an inspection of the charge centers of the hybrid Wannier functions, defined as the orbitals obtained by carrying out a Wannier transform on…

Mesoscale and Nanoscale Physics · Physics 2014-03-17 Maryam Taherinejad , Kevin F. Garrity , David Vanderbilt

We construct a heavy fermion representation for twisted bilayer graphene (TBG) systems. Two local orbitals (per spin/valley) are analytically found, which are exactly the maximally localized zero modes of the continuum Hamiltonian near the…

Strongly Correlated Electrons · Physics 2022-12-20 Hao Shi , Xi Dai

Despite much theoretical work, developing a comprehensive ab initio model for twisted bilayer graphene (TBG) has proven challenging due to the inherent trade-off between accurately describing the band structure and incorporating the…

Strongly Correlated Electrons · Physics 2025-09-25 Run Hou , Shouvik Sur , Lucas K. Wagner , Andriy H. Nevidomskyy

We propose a method for studying the strong interaction regimes in twisted bilayer graphene using hybrid Wannier functions, that are Wannier-like in one direction and Bloch-like in the other. We focus on the active bands as given by the…

Mesoscale and Nanoscale Physics · Physics 2021-03-24 Kasra Hejazi , Xiao Chen , Leon Balents

Since the discovery of superconductivity and correlated insulator at fractional electron fillings in the twisted bilayer graphene, most theoretical efforts have been focused on describing this system in terms of an effective extended…

Strongly Correlated Electrons · Physics 2019-04-24 Xiao-Chuan Wu , Chao-Ming Jian , Cenke Xu

With its monoelemental composition, various crystalline forms and an inherently strong spin-orbit coupling, bismuth has been regarded as an ideal prototype material to expand our understanding of topological electronic structures. In…

We build symmetry adapted maximally localized Wannier states, and construct the low energy tight binding model for the four narrow bands of the twisted bilayer graphene. We do so when the twist angle is commensurate, near the `magic' value,…

Strongly Correlated Electrons · Physics 2018-10-02 Jian Kang , Oskar Vafek

We investigate the interplay of band structure topology and localization properties of Wannier functions. To this end, we extend a recently proposed compressed sensing based paradigm for the search for maximally localized Wannier functions…

Mesoscale and Nanoscale Physics · Physics 2014-09-12 J. C. Budich , J. Eisert , E. J. Bergholtz , S. Diehl , P. Zoller

We study the atomic structure of twisted bilayer graphene, with very small mismatch angles ($\theta \sim 0.28^0$), a topic of intense recent interest. We use simulations, in which we combine a recently presented semi-empirical potential for…

Materials Science · Physics 2016-11-15 Sandeep K. Jain , Vladimir Juricic , Gerard T. Barkema

Topological flat bands at the Fermi level offer a promising platform to study a variety of intriguing correlated phase of matter. Here we present band engineering in the twisted orbital-active bilayers with spin-orbit coupling. The symmetry…

Mesoscale and Nanoscale Physics · Physics 2022-09-15 Huan Wang , Yadong Jiang , Zhaochen Liu , Jing Wang
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