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Related papers: Dynamic Kohn anomaly in twisted bilayer graphene

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Twisted double bilayer graphene (tDBG) has emerged as an especially rich platform for studying strongly correlated and topological states of matter. The material features moir\'e bands that can be continuously deformed by both perpendicular…

Mesoscale and Nanoscale Physics · Physics 2023-12-05 Minhao He , Jiaqi Cai , Ya-Hui Zhang , Yang Liu , Yuhao Li , Takashi Taniguchi , Kenji Watanabe , David H. Cobden , Matthew Yankowitz , Xiaodong Xu

The phonon dispersion of graphene on Ir(111) has been determined by means of angle-resolved inelastic electron scattering and density functional calculations. Kohn anomalies of the highest optical-phonon branches are observed at the…

Materials Science · Physics 2015-06-17 M. Endlich , A. Molina-Sánchez , L. Wirtz , J. Kröger

We theoretically study the effects of electron-electron interaction in twisted bilayer graphene in applied transverse dc electric field. When the twist angle is not very small, the electronic spectrum of the bilayer consists of four Dirac…

Strongly Correlated Electrons · Physics 2018-07-04 A. O. Sboychakov , A. V. Rozhkov , A. L. Rakhmanov , Franco Nori

The mechanism of charge carrier interaction in twisted bilayer graphene (TBG) remains an unresolved problem, where some researchers proposed the dominance of the electron-phonon interaction, while the others showed evidence for…

Mesoscale and Nanoscale Physics · Physics 2021-06-02 E. F. Talantsev

Magic-angle twisted bilayer graphene has recently become a thriving material platform realizing correlated electron phenomena taking place within its topological flat bands. Several numerical and analytical methods have been applied to…

Strongly Correlated Electrons · Physics 2021-09-17 Bin-Bin Chen , Yuan Da Liao , Ziyu Chen , Oskar Vafek , Jian Kang , Wei Li , Zi Yang Meng

Electron interactions in quantum materials fundamentally shape their energy bands and, with them, the material's most intriguing quantum phases. Magic angle twisted bilayer graphene (MATBG) has emerged as a model system, where flat bands…

Mesoscale and Nanoscale Physics · Physics 2025-06-27 J. Xiao , A. Inbar , J. Birkbeck , N. Gershon , Y. Zamir , T. Taniguchi , K. Watanabe , E. Berg , S. Ilani

Since their discovery, graphene-based systems represent an exceptional playground to explore the emergence of peculiar quantum effects. The present paper focuses on the anomalous appearence of strong infrared phonon resonances in the…

Mesoscale and Nanoscale Physics · Physics 2012-10-04 E. Cappelluti , L. Benfatto , M. Manzardo , A. B. Kuzmenko

A number of interesting physical phenomena have been discovered in magic-angle twisted bilayer graphene (MATBG), such as superconductivity, correlated gapped and gapless phases, etc. The gapped phases are believed to be symmetry-breaking…

Strongly Correlated Electrons · Physics 2024-01-19 Geng-Dong Zhou , Yi-Jie Wang , Ninghua Tong , Zhi-Da Song

Nanoscale twisted bilayer graphene (TBG) is quite instable and will change its structure to Bernal (or AB-stacking) bilayer with a much lower energy. Therefore, the lack of nanoscale TBG makes its electronic properties not accessible in…

Mesoscale and Nanoscale Physics · Physics 2017-09-27 Wen-Xiao Wang , Hua Jiang , Yu Zhang , Si-Yu Li , Haiwen Liu , Xinqi Li , Xiaosong Wu , Lin He

Twisted bilayer graphene aligned with hexagonal boron nitride (TBG/hBN) hosts rich topological and correlated quantum phases, such as (fractional) Chern insulators, whose character is dictated by the topology of the moir\'{e} flat band.…

Strongly Correlated Electrons · Physics 2026-05-01 Huiwen Wang , Wei Jiang

We find exact analytic expressions for the energies and wavefunctions of the charged and neutral excitations above the exact ground states (at rational filling per unit cell) of projected Coulomb Hamiltonians in twisted bilayer graphene.…

Strongly Correlated Electrons · Physics 2022-04-29 B. Andrei Bernevig , Biao Lian , Aditya Cowsik , Fang Xie , Nicolas Regnault , Zhi-Da Song

The interaction of graphene with metallic substrates reveals phenomena and properties of great relevance for applications in nanotechnology. In this review, the vibrational characterization by means of various inelastic scattering…

Materials Science · Physics 2016-01-08 Antonio Politano

The ground states of twisted bilayer graphene (TBG) at chiral and flat-band limit with integer fillings are known from exact solutions, while their dynamical and thermodynamical properties are revealed by unbiased quantum Monte Carlo (QMC)…

Strongly Correlated Electrons · Physics 2024-03-15 Cheng Huang , Xu Zhang , Gaopei Pan , Heqiu Li , Kai Sun , Xi Dai , Ziyang Meng

The quantum anomalous Hall (QAH) effect is sometimes observed in twisted bilayer graphene (tBG) when it is nearly aligned with an encapsulating hexagonal boron nitride (hBN) layer. We propose that the appearance or absence of the QAH effect…

Mesoscale and Nanoscale Physics · Physics 2021-02-17 Jingtian Shi , Jihang Zhu , A. H. MacDonald

Symmetry breaking is an effective tool for tuning the transport and topological properties of 2D layered materials. Among these materials, twisted bilayer graphene (TBG) has emerged as a promising platform for new physics, characterized by…

Mesoscale and Nanoscale Physics · Physics 2024-06-06 Cunyuan Jiang , Matteo Baggioli , Qing-Dong Jiang

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

We present electronic structure calculations of twisted double bilayer graphene (TDBG): A tetralayer graphene structure composed of two AB-stacked graphene bilayers with a relative rotation angle between them. Using first-principles…

Mesoscale and Nanoscale Physics · Physics 2019-11-05 F. J. Culchac , Rodrigo B. Capaz , Leonor Chico , E. Suarez Morell

We investigate the band structure of twisted monolayer-bilayer graphene (tMBG), or twisted graphene on bilayer graphene (tGBG), as a function of twist angles and perpendicular electric fields in search of optimum conditions for achieving…

Mesoscale and Nanoscale Physics · Physics 2020-07-15 Youngju Park , Bheema Lingam Chittari , Jeil Jung

The quantum corrections to the energies of the $\Gamma$ point optical phonon modes (Kohn anomalies) in graphene nanoribbons are investigated. We show theoretically that the longitudinal optical modes undergo a Kohn anomaly effect, while the…

The emergence of twistronics provides an unprecedented platform to modulate the band structure, resulting in exotic electronic phenomena ranging from ferromagnetism to superconductivity. However, such concept on phonon engineering is still…

Mesoscale and Nanoscale Physics · Physics 2020-08-25 Yufeng Zhang , Meng An , Dongxing Song , Haidong Wang , Weigang Ma , Xing Zhang