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The emergence of alternating twist multilayer graphene (ATMG) as a generalization of twisted bilayer graphene (TBG) raises the question - in what important ways do these systems differ? Here, we utilize ab-initio relaxation and…

Strongly Correlated Electrons · Physics 2021-11-24 Patrick J. Ledwith , Eslam Khalaf , Ziyan Zhu , Stephen Carr , Efthimios Kaxiras , Ashvin Vishwanath

We demonstrate the generic existence of Dirac cones in the full Bistritzer--MacDonald Hamiltonian for twisted bilayer graphene. Its complementary set, when Dirac cones are absent, is the set of magic angles. We show the stability of magic…

Mathematical Physics · Physics 2024-07-10 Simon Becker , Solomon Quinn , Zhongkai Tao , Alexander Watson , Mengxuan Yang

Recent experiments on magic-angle twisted bilayer graphene have discovered correlated insulating behavior and superconductivity at a fractional filling of an isolated narrow band. In this paper we show that magic-angle bilayer graphene…

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

An unconventional insulating phase and a superconducting phase were recently discovered in the twisted bilayer graphene [Y. Cao et al, Nature {\bf 556}, 80; {\bf 556}, 43 (2018)], but the relevant low-energy electronic states have not been…

Mesoscale and Nanoscale Physics · Physics 2019-05-02 Long Zhang

A theoretical model is presented to compute the electronic band structures and optical absorption spectra for twisted incommensurate few-layers graphene (tLFG) systems of arbitrary architecture. This is accomplished using an integrated…

Mesoscale and Nanoscale Physics · Physics 2015-04-07 D. Ghader , A. Khater , D. Szczȩśniak

We report a systematic plasmonic study of twisted bilayer graphene (TBLG) - two graphene layers stacked with a twist angle. Through real-space nanoimaging of TBLG single crystals with a wide distribution of twist angles, we find that TBLG…

Mesoscale and Nanoscale Physics · Physics 2023-01-30 Fengrui Hu , Suprem R Das , Yilong Luan , T. -F. Chung , Yong P. Chen , Zhe Fei

If we stack up two layers of graphene while changing their respective orientation by some twisting angle, we end up with a system that has striking differences when compared to single-layer graphene. For a very specific value of this twist…

Mesoscale and Nanoscale Physics · Physics 2024-09-18 Eduardo B. Molinero , Anushree Datta , María J. Calderón , Elena Bascones , Rui E. F. Silva

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 unusual properties of superconductivity in magic-angle twisted bilayer graphene (MATBG) have sparked enormous research interest. However, despite the dedication of intensive experimental efforts and the proposal of several possible…

Control of the interlayer twist angle in two-dimensional (2D) van der Waals (vdW) heterostructures enables one to engineer a quasiperiodic moir\'e superlattice of tunable length scale. In twisted bilayer graphene (TBG), the simple moir\'e…

Superlattices (SLs) in monolayer and bilayer graphene, formed by spatially periodic potential variations, lead to a modified bandstructure with extra finite-energy and zero-energy Dirac fermions with tunable anisotropic velocities. We…

Mesoscale and Nanoscale Physics · Physics 2012-05-14 Si Wu , Matthew Killi , Arun Paramekanti

Identifying the microscopic processes that limit conductivity is essential for understanding correlated and quantum-critical states in quantum materials. In twisted bilayer graphene (TBG) and other twist-controlled materials, the…

The incommensurate 30$^{\circ}$ twisted bilayer graphene (BG) possesses both relativistic Dirac fermions and quasiperiodicity with 12-fold rotational symmetry arising from the interlayer interaction…

Mesoscale and Nanoscale Physics · Physics 2022-03-14 Guodong Yu , Yunhua Wang , Mikhail I. Katsnelson , Hai-Qing Lin , Shengjun Yuan

2D materials based superlattices have emerged as a promising platform to modulate band structure and its symmetries. In particular, moir\'e periodicity in twisted graphene systems produces flat Chern bands. The recent observation of…

We analyze a description of twisted graphene bilayers, that incorporates deformation of the layers due to the nature modern interlayer potentials, and a modification of the hopping parameters between layers in the light of the classic…

Strongly Correlated Electrons · Physics 2019-05-29 Francisco Guinea , Niels R. Walet

Van der Waals (vdW) heterostructures are an emergent class of metamaterials comprised of vertically stacked two-dimensional (2D) building blocks, which provide us with a vast tool set to engineer their properties on top of the already rich…

The interlayer coupling can be used to engineer the electronic structure of van der Waals heterostructures (superlattices) to obtain properties that are not possible in a single material. So far research in heterostructures has been focused…

Rotational misalignment or twisting of two mono-layers of graphene strongly influences its electronic properties. Structurally, twisting leads to large periodic supercell structures, which in turn can support intriguing strongly correlated…

When using hexagonal boron-nitride (hBN) as a substrate for graphene, the resulting moir\'e pattern creates secondary Dirac points. By encapsulating a multilayer graphene within aligned hBN sheets the controlled moir\'e stacking may offer…

Mesoscale and Nanoscale Physics · Physics 2023-02-14 Robin Smeyers , Lucian Covaci , Milorad V. Milošević
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