English
Related papers

Related papers: Optical Absorption in Twisted Bilayer Graphene

200 papers

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

Twisted bilayer graphene (tBLG) provides us with a large rotational freedom to explore new physics and novel device applications, but many of its basic properties remain unresolved. Here we report the synthesis and systematic Raman study of…

Magic-angle twisted bilayer graphene exhibits quasi-flat low-energy bands with Van Hove singularities close to the Fermi level. These singularities play an important role in the exotic phenomena observed in this material, such as…

Mesoscale and Nanoscale Physics · Physics 2022-12-08 Aleksander Sanjuan Ciepielewski , Jakub Tworzydło , Timo Hyart , Alexander Lau

This work theoretically explores how to emulate twisted double bilayer graphene with ultracold atoms in multiorbital optical lattices. In particular, the quadratic band touching of Bernal stacked bilayer graphene is emulated using a square…

Quantum Gases · Physics 2021-12-28 Junhyun Lee , J. H. Pixley

We present a study of the nonlinear optical response of twisted bilayer graphene. We discuss the contribution of the Berry phase to the non-linearity when inversion symmetry is broken, thus underlining the interplay between band and real…

Mesoscale and Nanoscale Physics · Physics 2022-07-12 Leone Di Mauro Villari , Alessandro Principi

We model the low energy dynamics of graphene in the continuum in terms of a version of Reduced Quantum Electrodynamics restricting fermions to a (2+1)-dimensional brane, whilst photons remain within the (3+1)-dimensional bulk. For charge…

Mesoscale and Nanoscale Physics · Physics 2016-05-25 Saúl Hernández-Ortiz , David Valenzuela , Alfredo Raya , Saúl Sánchez-Madrigal

We address the question of the optimal broadband absorption of waves in an open, dissipative system. We develop a general framework for absorption induced by multiple overlapping resonances, based on quasi-normal modes and radiative and…

Optics · Physics 2024-07-30 Stéphane Collin , Maxime Giteau

We have used scanning tunneling microscopy and spectroscopy to resolve the spatial variation of the density of states of twisted graphene layers on top of a highly oriented pyrolytic graphite substrate. Owing to the twist a moire pattern…

We numerically investigate the electronic transport properties between two mesoscopic graphene disks with a twist by employing the density functional theory coupled with non-equilibrium Green's function technique. By attaching two graphene…

Mesoscale and Nanoscale Physics · Physics 2020-07-01 Yulei Han , Yafei Ren , Xinlong Dong , Junjie Zeng , Wei Ren , Zhenhua Qiao

A simple analysis is performed for the absorption properties of graphene; sandwiched between two media. For a proper choice of media and graphene doping/gating one can approach 50-100% absorption in the GHz-THz range for the one atom thick…

Optics · Physics 2012-01-17 S. P. Apell , G. W. Hanson , C. Hägglund

We present a theoretical study of the local optical conductivity, plasmon spectra, and thermoelectric properties of twisted bilayer graphene (TBG) at different filling factors and twist angles $\theta$. Our calculations are based on the…

Mesoscale and Nanoscale Physics · Physics 2020-09-04 Pietro Novelli , Iacopo Torre , Frank H. L. Koppens , Fabio Taddei , Marco Polini

The requirements for broadband photodetection are becoming exceedingly demanding in hyperspectral imaging. Whilst intrinsic photoconductor arrays based on mercury cadmium telluride represent the most sensitive and suitable technology, their…

The electronic and optical properties of mono, di, tri, and tetravacancies in graphene are studied in comparison to each other, using density functional theory. In addition, oxidized monovacancies are considered for different oxygen…

Mesoscale and Nanoscale Physics · Physics 2013-11-12 N. Singh , T. P. Kaloni , Udo Schwingenschlögl

Twisted Bilayer Graphene at the magic twist angle features flat energy bands, which lead to superconductivity and strong correlation physics. These unique properties are typically limited to a narrow range of twist angles around the magic…

Strongly Correlated Electrons · Physics 2020-10-20 Or Katz , Gil Refael , Netanel H. Lindner

Twisted bilayer graphene with a twist angle of around 1.1{\deg} features a pair of isolated flat electronic bands and forms a strongly correlated electronic platform. Here, we use scanning tunneling microscopy to probe local properties of…

Using Linear Response Theory, with appropriate wave functions and energies from perturbation method, the absorption profiles can be calculated for all three classes of mixed-valence systems as defined by Robin and Day : Class III…

Materials Science · Physics 2024-10-18 Kin Yip Wong

The low energy electronic spectra of rotationally faulted graphene bilayers are studied using a long wavelength theory applicable to general commensurate fault angles. Lattice commensuration requires low energy electronic coherence across a…

Mesoscale and Nanoscale Physics · Physics 2015-05-18 E. J. Mele

The frequency-dependent conductivity is studied for both the one-dimensional Hubbard model and a model of spinless fermions, using a selection rule, the Bethe ansatz energy eigenstates, and conformal invariance. For densities where the…

Condensed Matter · Physics 2007-05-23 J. M. P. Carmelo , P. D. Sacramento , N. M. R. Peres , D. Baeriswyl

We present a comprehensive first-principles study of twisted bilayer graphene (tBLG) for a wide range of twist angles, with a focus on structural and electronic properties. By employing density functional theory (DFT) with an optimized…

Mesoscale and Nanoscale Physics · Physics 2026-05-13 Albert Zhu , Daniel Bennett , Daniel T. Larson , Mohammed M. Al Ezzi , Efstratios Manousakis , Efthimios Kaxiras

Using the tight binding and Pariser-Parr-Pople (PPP) model Hamiltonians, we study the electronic structure and optical response of multilayer armchair graphene nanoribbons (AGNRs), both with and without a gate bias. In particular, the…

Materials Science · Physics 2015-03-19 Kondayya Gundra , Alok Shukla