English
Related papers

Related papers: Graph Theorem for Chiral Exact Flat Bands at Charg…

200 papers

We consider a family of twisted graphene multilayers consisting of $n$-untwisted chirally stacked layers, e.g., AB, ABC, etc, with a single twist on top of $m$-untwisted {chirally stacked} layers. Upon neglecting both trigonal warping terms…

Strongly Correlated Electrons · Physics 2022-05-20 Patrick J. Ledwith , Ashvin Vishwanath , Eslam Khalaf

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 paper discusses the chiral tunnelling of charge carriers through double barrier structure in twisted graphene bilayer. The theoretical analysis investigates the transmission probability for various system parameters under both symmetric…

Mesoscale and Nanoscale Physics · Physics 2023-07-31 A. Bahlaoui , Y. Zahidi

Twisted bilayer graphene (TBG) is known for exhibiting highly correlated phases at magic angles due to the emergence of flat bands that enhance electron-electron interactions. In the TBG chiral model, electronic wave function properties…

Mesoscale and Nanoscale Physics · Physics 2023-09-15 Leonardo A. Navarro-Labastida , Gerardo G. Naumis

We propose models of twisted multilayer graphene that exhibit exactly flat Bloch bands with arbitrary Chern numbers and ideal band geometries. The models are constructed by twisting two sheets of Bernal-stacked multiple graphene layers with…

Mesoscale and Nanoscale Physics · Physics 2023-12-19 Jie Wang , Zhao Liu

A major hurdle in understanding the phase diagram of twisted bilayer graphene (TBLG) are the roles of lattice relaxation and electronic structure on isolated band flattening near magic twist angles. In this work, the authors develop an…

Mesoscale and Nanoscale Physics · Physics 2024-03-28 Shivesh Pathak , Tawfiqur Rakib , Run Hou , Andriy Nevidomskyy , Elif Ertekin , Harley T. Johnson , Lucas K. Wagner

We demonstrate that a single layer of graphene subject to a superlattice potential nearly commensurate to a $\sqrt{3} \times \sqrt{3}$ supercell exactly maps to the chiral model of twisted bilayer graphene, albeit with half as many degrees…

Mesoscale and Nanoscale Physics · Physics 2024-01-18 Valentin Crépel , Aaron Dunbrack , Daniele Guerci , John Bonini , Jennifer Cano

We theoretically study the electronic structure of small-angle twisted bilayer graphene with a large potential asymmetry between the top and bottom layers. We show that the emergent helical states known to appear on the triangular AB-BA…

Mesoscale and Nanoscale Physics · Physics 2020-03-18 Bonnie Tsim , Nguyen N. T. Nam , Mikito Koshino

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

Owing to the interaction between the layers, the twisted bilayer two-dimensional materials exhibit numerous unique optical and electronic properties different from the monolayer counterpart, and have attracted tremendous interests in…

Mesoscale and Nanoscale Physics · Physics 2021-08-18 Yabin Ma , Tao Ouyang , Yuanping Chen , Yuee Xie

The eigenstates of an electron in the chiral two-dimensional electron gas (C2DEG) formed in an AB-stacked bilayer or an ABC-stacked trilayer graphene is a spinor with $4$ or $6$ components respectively. These components give the amplitude…

Mesoscale and Nanoscale Physics · Physics 2014-01-08 R. Côté , Manuel Barrette

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

We investigate the electronic structure of a twisted multilayer graphene system forming a moir\'e pattern. We consider small twist angles separating the graphene sheets and develop a low-energy theory to describe the coupling of Dirac Bloch…

Mesoscale and Nanoscale Physics · Physics 2019-07-17 Christophe Mora , Nicolas Regnault , B. Andrei Bernevig

We study the atomic and electronic structures of the commensurate double moir\'{e} superlattices in fully relaxed twisted bilayer graphene (TBG) nearly aligned with the hexagonal boron nitride (BN). The single-particle effective Hamiltonian…

Mesoscale and Nanoscale Physics · Physics 2020-07-31 Xianqing Lin , Jun Ni

Twisted bilayer graphene (TBG) hosts nearly flat bands with narrow bandwidths of a few meV at certain {\em magic} twist angles. Here we show that in twisted gapped Dirac material bilayers, or massive twisted bilayer graphenes (MTBG),…

Mesoscale and Nanoscale Physics · Physics 2020-03-18 Srivani Javvaji , Jinhua Sun , Jeil Jung

Twisted two-dimensional structures open new possibilities in band structure engineering. At magic twist angles, flat bands emerge, which give a new drive to the field of strongly correlated physics. In twisted double bilayer graphene dual…

Topological flat bands, such as the band in twisted bilayer graphene, are becoming a promising platform to study topics such as correlation physics, superconductivity, and transport. In this work, we introduce a generic approach to…

Mesoscale and Nanoscale Physics · Physics 2021-01-04 Da-Shuai Ma , Yuanfeng Xu , Christie S. Chiu , Nicolas Regnault , Andrew A. Houck , Zhida Song , B. Andrei Bernevig

Twisted bilayer graphene with a twist angle of around 1.1{\deg} features a pair of isolated flat electronic bands and forms a strongly correlated electronic platform. Here, we use scanning tunneling microscopy to probe local properties of…

Transport experiments in twisted bilayer graphene revealed multiple superconducting domes separated by correlated insulating states. These properties are generally associated with strongly correlated states in a flat mini-band of the…

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