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Related papers: Dynamic Kohn anomaly in twisted bilayer graphene

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Moir\'e phonons describe collective vibrations of a moir\'e superlattice produced by long-wavelength relative displacements of the constituent layers. Despite coming from the backfolding of the acoustic phonons of the individual layers,…

Mesoscale and Nanoscale Physics · Physics 2026-01-13 Alejandro Ramos-Alonso , Hector Ochoa

Twisted bilayer graphene (tBLG) devices with ion gel gate dielectrics are studied using Raman spectroscopy in the twist angle regime where a resonantly enhanced G band can be observed. We observe prominent splitting and intensity quenching…

Mesoscale and Nanoscale Physics · Physics 2015-02-18 Ting-Fung Chung , Rui He , Tai-Lung Wu , Yong P. Chen

Recently, the twist-angle effect on 2D van der Walls (vdW) materials, such as bilayer graphene, has attracted great attention. Many novel electronic, magnetic and even optical properties induced by such effect have been discovered. However,…

Mesoscale and Nanoscale Physics · Physics 2023-12-20 H. F. Feng , B. Liu , Zhi-Xin Guo

By comparing with recently available experimental data from several groups, we critically discuss the manifestation of continuum many body interaction effects in twisted bilayer graphene (tBLG) with small twist angles and low carrier…

Mesoscale and Nanoscale Physics · Physics 2020-06-02 Sankar Das Sarma , Fengcheng Wu

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

Twisted trilayer graphene is a particularly promising moir\'e superlattice system, due to its tunability, strong superconductivity, and complex electronic symmetry breaking. Motivated by these properties, we study lattice relaxation and the…

Mesoscale and Nanoscale Physics · Physics 2022-12-23 Rhine Samajdar , Yanting Teng , Mathias S. Scheurer

We develop a theory for the renormalization of the phonon energy dispersion in graphene due to the combined effects of both Coulomb and electron-phonon (e-ph) interactions. We obtain the renormalized phonon energy spectrum by an exact…

Materials Science · Physics 2009-11-13 Wang-Kong Tse , Ben Yu-Kuang Hu , S. Das Sarma

We present a computational study of the phonon linewidths in twisted bilayer graphene arising from electron-phonon interactions and anharmonic effects. The electronic structure is calculated using distance-dependent transfer integrals based…

Mesoscale and Nanoscale Physics · Physics 2024-10-10 Shinjan Mandal , Indrajit Maity , H. R. Krishnamurthy , Manish Jain

In twisted bilayer graphene (TBG) a moir\'e pattern forms that introduces a new length scale to the material. At the 'magic' twist angle of 1.1{\deg}, this causes a flat band to form, yielding emergent properties such as correlated…

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…

In neutral graphene, two prominent cusps known as Kohn anomalies are found in the phonon dispersion of the highest optical phonon at $q=\Gamma$ (LO branch) and $q=K$ (TO branch), reflecting a significant electron-phonon coupling to undoped…

Mesoscale and Nanoscale Physics · Physics 2015-08-18 Antonio Politano , Fernando de Juan , Gennaro Chiarello , Herbert A. Fertig

We study the interacting transport properties of twisted bilayer graphene (TBG) using the topological heavy-fermion (THF) model. In the THF model, TBG comprises localized, correlated $f$-electrons and itinerant, dispersive $c$-electrons. We…

Strongly Correlated Electrons · Physics 2024-02-23 Dumitru Călugăru , Haoyu Hu , Rafael Luque Merino , Nicolas Regnault , Dmitri K. Efetov , B. Andrei Bernevig

The electron-phonon interaction (EPI) is instrumental in a wide variety of phenomena in solid-state physics, such as electrical resistivity in metals, carrier mobility, optical transition and polaron effects in semiconductors, lifetime of…

On flat bands of the magic-angle twisted bilayer graphene, exotic correlation physics unfolds. Phonons, through mediating an effective electron-electron interaction, can play a crucial role in selecting various electronic phases. In this…

Strongly Correlated Electrons · Physics 2025-07-03 Yi-Jie Wang , Geng-Dong Zhou , Biao Lian , Zhi-Da Song

We present a theory of phonon-mediated superconductivity in near magic angle twisted bilayer graphene. Using a microscopic model for phonon coupling to moir\'e band electrons, we find that phonons generate attractive interactions in both…

Superconductivity · Physics 2018-12-19 Fengcheng Wu , A. H. MacDonald , Ivar Martin

We study the anomalous Hall effect, magneto-optical properties, and nonlinear optical properties of twisted bilayer graphene (TBG) aligned with hexagonal boron nitride (hBN) substrate as well as twisted double bilayer graphene systems. We…

Mesoscale and Nanoscale Physics · Physics 2021-01-27 Jianpeng Liu , Xi Dai

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 (tBLG) has been studied extensively owing to its wealth of symmetry-broken phases, correlated Chern insulators, orbital magnetism, and superconductivity. In particular, the anomalous Hall effect (AHE)…

Mesoscale and Nanoscale Physics · Physics 2022-12-13 Chun-Chih Tseng , Xuetao Ma , Zhaoyu Liu , Kenji Watanabe , Takashi Taniguchi , Jiun-Haw Chu , Matthew Yankowitz

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

Twisted bilayer graphene (tBLG) provides a fascinating platform for engineering flat bands and inducing correlated phenomena. By designing the stacking architecture of graphene layers, twisted multilayer graphene can exhibit different…