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The recent observed anomalous Hall effect in magic angle twisted bilayer graphene (TBG) aligned to hexagonal boron nitride (hBN) and unconventional ferroelectricity in Bernal bilayer graphene sandwiched by hBN present a new platform to tune…

Mesoscale and Nanoscale Physics · Physics 2024-02-01 Min Long , Zhen Zhan , Pierre A. Pantaleón , Jose Ángel Silva-Guillén , Francisco Guinea , Shengjun Yuan

We investigate the topological properties of Floquet-engineered twisted bilayer graphene above the magic angle driven by circularly polarized laser pulses. Employing a full Moir\'e-unit-cell tight-binding Hamiltonian based on…

Materials Science · Physics 2019-09-30 Gabriel E. Topp , Gregor Jotzu , James W. McIver , Lede Xian , Angel Rubio , Michael A. Sentef

We show that the electronic structure of the low-energy bands in the small angle-twisted bilayer graphene consists of a series of semi-metallic and topological phases. In particular we are able to prove, using an approximate low-energy…

Mesoscale and Nanoscale Physics · Physics 2019-07-24 Zhida Song , Zhijun Wang , Wujun Shi , Gang Li , Chen Fang , B. Andrei Bernevig

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

In this work the effects of defects in the superconducting phases of the twisted bilayer graphene (TBG) are investigated. A will-accepted low energy effective model and a non-magnetic impurity potential to mimic defects are employed.…

Superconductivity · Physics 2020-09-08 Hui Yang , Zhi-Qiang Gao , Fa Wang

When two sheets of graphene stack in a twisted bilayer graphene (tBLG) configuration, the resulting constrained overlap between interplanar 2p orbitals produce angle-tunable electronic absorption resonances. Using a novel combination of…

Mesoscale and Nanoscale Physics · Physics 2016-01-13 Hiral Patel , Lola Brown , Yufeng Liang , Li Yang , Jiwoong Park , Matt W. Graham

Controlling the bandstructure of Dirac materials is of wide interest in current research but has remained an outstanding challenge for systems such as monolayer graphene. In contrast, Bernal bilayer graphene (BLG) offers a highly flexible…

We review the electronic properties of bilayer graphene, beginning with a description of the tight-binding model of bilayer graphene and the derivation of the effective Hamiltonian describing massive chiral quasiparticles in two parabolic…

Mesoscale and Nanoscale Physics · Physics 2013-04-23 Edward McCann , Mikito Koshino

Van der Waals (vdW) heterostructures consisting of Bernal bilayer graphene (BLG) and hexagonal boron nitride (hBN) are investigated. By performing first-principles calculations we capture the essential BLG band structure features for…

Mesoscale and Nanoscale Physics · Physics 2023-09-27 Klaus Zollner , Eike Icking , Jaroslav Fabian

We show that the recently observed superconductivity in twisted bilayer graphene (TBG) can be explained as a consequence of the Kohn-Luttinger (KL) instability which leads to an effective attraction between electrons with originally…

Mesoscale and Nanoscale Physics · Physics 2019-01-21 J. González , T. Stauber

We describe how the out-of-plane dielectric polarizability of monolayer graphene influences the electrostatics of bilayer graphene -- both Bernal (BLG) and twisted (tBLG). We compare the polarizability value computed using density…

We study the electronic and topological properties of fully relaxed twisted bilayer (TBG) and double bilayer (TDBG) graphene under perpendicular pressure. An approach has been proposed to obtain the equilibrium in-plane structural…

Mesoscale and Nanoscale Physics · Physics 2020-07-20 Xianqing Lin , Haotian Zhu , Jun Ni

The folding of monolayer graphene leads to new layered systems, termed twisted bilayer graphene (TBG), generally displaying a certain interlayer rotation away from crystallographic alignment. We here present an atomic force microscopy study…

Materials Science · Physics 2016-08-30 Johannes C. Rode , Christopher Belke , Hennrik Schmidt , Rolf J. Haug

Small-twist-angle bilayer graphene supports strongly correlated insulating states and superconductivity. Twisted few-layer graphene systems are likely to open up new directions for strong correlation physics in moir\'e superlattices. We…

Materials Science · Physics 2019-07-30 Xiao Li , Fengcheng Wu , Allan H. MacDonald

For the unconventional superconducting phases in moire materials, a critical question is the role played by electronic interactions in the formation of Cooper pairs. In twisted bilayer graphene (tBLG), the strength of electronic…

The effect of an hexagonal boron nitride (hBN) layer close aligned with twisted bilayer graphene (TBG) is studied. At sufficiently low angles between twisted bilayer graphene and hBN, $\theta_{hBN} \lesssim 2^\circ$, the graphene electronic…

Strongly Correlated Electrons · Physics 2020-10-28 Tommaso Cea , Pierre A. Pantaleon , Francisco Guinea

Bilayer graphene (BLG) with a tunable bandgap appears interesting as an alternative to graphene for practical applications, thus its transport properties are being actively pursued. Using density functional theory and perturbation analysis,…

Materials Science · Physics 2015-05-11 Changwon Park , Junga Ryou , Suklyun Hong , Bobby Sumpter , Gunn Kim , Mina Yoon

Bilayer graphene is a recently isolated and intriguing class of many-body systems with massive chiral quasiparticles. We present theoretical results for the electronic compressibility of bilayer graphene that are based on a four-band…

Mesoscale and Nanoscale Physics · Physics 2010-10-06 Giovanni Borghi , Marco Polini , Reza Asgari , A. H. MacDonald

Electronic correlations in two-dimensional materials play a crucial role in stabilising emergent phases of matter. The realisation of correlation-driven phenomena in graphene has remained a longstanding goal, primarily due to the absence of…

Mesoscale and Nanoscale Physics · Physics 2023-09-19 Saisab Bhowmik , Arindam Ghosh , U. Chandni

Moir\'e superlattices in twisted homo-bilayers have revealed exotic electronic states, including unconventional superconductivity and correlated insulating phases. However, their fabrication process often introduces moir\'e disorders,…

Mesoscale and Nanoscale Physics · Physics 2025-02-13 Zeyu Liu , Xianghua Kong , Zewen Wu , Linwei Zhou , Jingsi Qiao , Wei Ji