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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…

Magic-angle twisted bilayer graphene is the best studied physical platform featuring moire potential induced narrow bands with non-trivial topology and strong electronic correlations. Despite their significance, the Chern insulating states…

Mesoscale and Nanoscale Physics · Physics 2024-06-11 Xiaoyu Wang , Oskar Vafek

Starting with twisted bilayer graphene, graphene-based moir\'e materials have recently been established as a new platform for studying strong electron correlations. In this paper, we study twisted graphene monolayers on trilayer graphene…

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

We study the electronic structure of multilayer graphenes with a mixture of Bernal and rhombohedral stacking and propose a general scheme to understand the electronic band structure of an arbitrary configuration. The system can be viewed as…

Mesoscale and Nanoscale Physics · Physics 2015-06-12 Mikito Koshino , Edward McCann

Twisted graphene bilayers provide a versatile platform to engineer metamaterials with novel emergent properties by exploiting the resulting geometric moir\'{e} superlattice. Such superlattices are known to host bulk valley currents at tiny…

Mesoscale and Nanoscale Physics · Physics 2019-09-04 T. M. R. Wolf , J. L. Lado , G. Blatter , O. Zilberberg

From atomic crystals to macroscopic material structures, twisted bilayer systems have emerged as a promising route to control wave phenomena. In few-layer van der Waals (vdW) materials, however, the intrinsically weak interlayer coupling…

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

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

Electronic structures and their Landau quantizations in twisted graphene bilayer and trilayer are investigated using scanning tunnelling microscopy and spectroscopy. In the twisted trilayer, the top graphene layer and second layer are AB…

Mesoscale and Nanoscale Physics · Physics 2015-01-09 Long-Jing Yin , Jia-Bin Qiao , Wei Yan , Rui Xu , Rui-Fen Dou , Jia-Cai Nie , Lin He

The observation of zero field fractional quantum Hall analogs in twisted transition metal dichalcogenides (TMDs) asks for a deeper understanding of what mechanisms lead to topological flat bands in two-dimensional heterostructures, and what…

Mesoscale and Nanoscale Physics · Physics 2024-05-10 Valentin Crépel , Nicolas Regnault , Raquel Queiroz

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 introduce a scheme by which flat bands with higher Chern number $\vert C\vert>1$ can be designed in ultracold gases through a coherent manipulation of Bloch bands. Inspired by quantum-optics methods, our approach consists in creating a…

Quantum Gases · Physics 2021-05-26 Mateusz Łącki , Jakub Zakrzewski , Nathan Goldman

The interplay between moir\'e flat bands originating from different valleys can give rise to a variety of exotic quantum phases. In this work, we investigate the electronic properties of twisted mono-bilayer (A-AB) and mono-trilayer (A-ABA)…

A large number of recent works point to the emergence of intriguing analogs of fractional quantum Hall states in lattice models due to effective interactions in nearly flat bands with Chern number C=1. Here, we provide an intuitive and…

Strongly Correlated Electrons · Physics 2013-01-01 Maximilian Trescher , Emil J. Bergholtz

We report on a double moir\'e system consisting of four graphene layers, where the top and bottom pairs form small-twist-angle bilayer graphene, and the middle interface has a large rotational mismatch. This system shows clear signatures of…

We present atomistic calculations on structural and electronic properties of twisted double bilayer graphene (TDBG) consisting of two sets of rotationally misaligned Bernal-stacked bilayer graphene. Obtained equilibrium atomic structures…

Mesoscale and Nanoscale Physics · Physics 2019-11-20 Young Woo Choi , Hyoung Joon Choi

The observation of delicate correlated phases in twisted heterostructures of graphene and transition metal dichalcogenides suggests that moir\'e flat bands are intrinsically resilient against certain types of disorder. Here, we investigate…

Mesoscale and Nanoscale Physics · Physics 2025-07-22 Valentin Crépel , Peize Ding , Nishchhal Verma , Nicolas Regnault , Raquel Queiroz

We show that rhombohedral four-layer graphene (4LG) nearly aligned with a hexagonal boron nitride (hBN) substrate often develops nearly flat isolated low energy bands with non-zero valley Chern numbers. The bandwidths of the isolated…

Mesoscale and Nanoscale Physics · Physics 2023-11-28 Youngju Park , Yeonju Kim , Bheema Lingam Chittari , Jeil Jung

The interplay of twist and strain in bilayer graphene enables the formation of moir\'e patterns and narrow bands that host correlated and topological phases. While magic-angle twisted bilayer graphene has been widely studied, strain…

Mesoscale and Nanoscale Physics · Physics 2026-03-10 Federico Escudero , Dong Wang , Pierre A. Pantaleón , Shengjun Yuan , Francisco Guinea , Zhen Zhan