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Related papers: Electron-phonon coupling in a magic-angle twisted-…

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Magneto Raman scattering study of the E$_{2g}$ optical phonons in multi-layer epitaxial graphene grown on a carbon face of SiC are presented. At 4.2K in magnetic field up to 33 T, we observe a series of well pronounced avoided crossings…

Materials Science · Physics 2015-05-13 C. Faugeras , M. Amado , P. Kossacki , M. Orlita , M. Sprinkle , C. Berger , W. A. de Heer , M. Potemski

The rich phenomenology of twisted bilayer graphene (TBG) near the magic angle is believed to arise from electron correlations in topological flat bands. An unbiased approach to this problem is highly desirable, but also particularly…

Strongly Correlated Electrons · Physics 2021-09-28 Johannes S. Hofmann , Eslam Khalaf , Ashvin Vishwanath , Erez Berg , Jong Yeon Lee

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

Electron-phonon coupling directly determines the stability of cooperative order in solids, including superconductivity, charge and spin density waves. Therefore, the ability to enhance or reduce electron-phonon coupling by optical driving…

Through extensive self-consistent Hartree-Fock calculations in a tight-binding model of twisted bilayer graphene (TBG), we show that many-body effects lead to a considerable increase of the bandwidth of the flat bands and, concomitantly, to…

Mesoscale and Nanoscale Physics · Physics 2026-04-30 Miguel Sánchez Sánchez , José González , Tobias Stauber

Understanding the normal-metal state transport in twisted bilayer graphene near magic angle is of fundamental importance as it provides insights into the mechanisms responsible for the observed strongly correlated insulating and…

Mesoscale and Nanoscale Physics · Physics 2024-02-19 Gargee Sharma , Indra Yudhistira , Nilotpal Chakraborty , Derek Y. H. Ho , Michael S. Fuhrer , Giovanni Vignale , Shaffique Adam

We report a comprehensive study of the tuning with electric fields of the resonant magneto-exciton optical phonon coupling in gated graphene. For magnetic fields around $B \sim 25$ T which correspond to the range of the fundamental…

Mesoscale and Nanoscale Physics · Physics 2014-05-14 P. Leszczynski , Z. Han , A. A. L. Nicolet , B. A. Piot , P. Kossacki , M. Orlita , V. Bouchiat , D. M. Basko , M. Potemski , C. Faugeras

Electron-phonon coupling in graphene is extensively modeled and simulated from first principles. We find that using an accurate model for the polarizations of the acoustic phonon modes is crucial to obtain correct numerical results. The…

The effective interaction between electrons in two-dimensional materials can be modified by their environment, enabling control of electronic correlations and phases. Here, we study the dependence of electronic correlations in twisted…

Strongly Correlated Electrons · Physics 2020-04-15 Zachary A. H. Goodwin , Valerio Vitale , Fabiano Corsetti , Dmitri K. Efetov , Arash A. Mostofi , Johannes Lischner

Recently, alternating twist multilayer graphene (ATMG) has emerged as a family of moir\'e systems that share several fundamental properties with twisted bilayer graphene, and are expected to host similarly strong electron-electron…

Mesoscale and Nanoscale Physics · Physics 2022-07-12 G. William Burg , Eslam Khalaf , Yimeng Wang , Kenji Watanabe , Takashi Taniguchi , Emanuel Tutuc

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…

Interactions among electrons and the topology of their energy bands can create novel quantum phases of matter. Most topological electronic phases appear in systems with weak electron-electron interactions. The instances where topological…

Mesoscale and Nanoscale Physics · Physics 2020-12-25 Kevin P. Nuckolls , Myungchul Oh , Dillon Wong , Biao Lian , Kenji Watanabe , Takashi Taniguchi , B. Andrei Bernevig , Ali Yazdani

We consider twisted bilayer and trilayer graphene in the presence of Rashba spin-orbit coupling and explore the physics of Moir\'e spintronics. The electronic charge density has a sharp step right at the magic angles $\theta_m$. As a…

Mesoscale and Nanoscale Physics · Physics 2022-08-17 Yshai Avishai , Yehuda Band

Magic-angle twisted bilayer graphene is a tunable material with remarkably flat energy bands near the Fermi level, leading to fascinating transport properties and correlated states at low temperatures. However, grown pristine samples of…

Mesoscale and Nanoscale Physics · Physics 2024-03-29 Aleksander Sanjuan Ciepielewski , Jakub Tworzydło , Timo Hyart , Alexander Lau

Magic-angle twisted bilayer graphene (MATBG) has been extensively explored both theoretically and experimentally as a suitable platform for a rich and tunable phase diagram that includes ferromagnetism, charge order, broken symmetries, and…

Mesoscale and Nanoscale Physics · Physics 2024-05-16 Lauro B. Braz , George B. Martins , Luis G. G. V. Dias da Silva

Bilayer graphene twisted at the angle of about 1.1{\deg} better known as magic angle, exhibits ultra-flat moir\'e superlattice bands that are a source of highly-tunable, exotic quantum phenomena. Such phenomena, like superconductivity,…

Strongly Correlated Electrons · Physics 2024-11-05 Giovanna Feraco , Wissem Boubaker , Petra Rudolf , Antonija Grubišić-Čabo

Magic-angle twisted bilayer graphene (MATBG) exhibits a range of correlated phenomena that originate from strong electron-electron interactions. These interactions make the Fermi surface highly susceptible to reconstruction when $ \pm 1,…

We present a theoretical study of the intrinsic plasmonic properties of twisted bilayer graphene (TBG) as a function of the twist angle $\theta$ (and other microscopic parameters such as temperature and filling factor). Our calculations,…

Mesoscale and Nanoscale Physics · Physics 2024-09-06 Lorenzo Cavicchi , Iacopo Torre , Pablo Jarillo-Herrero , Frank H. L. Koppens , Marco Polini

The phonon spectra of twisted bilayer graphene (tBLG) are analyzed for a series of 692 twisting angle values in the $[0,30{\degree}]$ range. The evolution of the phonon bandstructure as a function of twist angle is examined using a band…

Mesoscale and Nanoscale Physics · Physics 2020-01-01 Michael Lamparski , Benoit Van Troeye , Vincent Meunier

Recent optical studies in c-axis oriented superconducting MgB$_2$ films indicate that the electron-phonon coupling is weak [tu01]. We reinforce this conclusion by examining the raw reflectance data; its frequency dependence is incompatible…

Superconductivity · Physics 2009-11-07 F. Marsiglio