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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

Moir\'e systems displaying flat bands have emerged as novel platforms to study correlated electron phenomena. Insulating and superconducting states appear upon doping magic angle twisted bilayer graphene (TBG), and there is evidence of…

Strongly Correlated Electrons · Physics 2021-05-17 M. J. Calderón , E. Bascones

We have calculated the optical conductivity of a disorder-free single graphene sheet in the presence of spin-orbit coupling, using the Kubo formalism. Both intrinsic and structural-inversion-asymmetry induced types of spin splitting are…

Mesoscale and Nanoscale Physics · Physics 2010-01-21 P. Ingenhoven , J. Z. Bernad , U. Zuelicke , R. Egger

We study the optical conductivity in the low-energy regime of gapped mono- and bilayer graphene. A scaling relation is found, in which the four parameters frequency, gap, Fermi energy and temperature appear only as combination of three…

Materials Science · Physics 2010-01-20 K. Ziegler , A. Sinner

We calculate the dynamical conductivity of AA-stacked bilayer graphene as a function of frequency and in the presence of a finite chemical potential due to charging. Unlike the monolayer, we find a Drude absorption at charge neutrality in…

Mesoscale and Nanoscale Physics · Physics 2013-03-01 Calvin J. Tabert , Elisabeth J. Nicol

Magic angle twisted bilayer graphene has emerged as a powerful platform for studying strongly correlated electron physics, owing to its almost dispersionless low-energy bands and the ability to tune the band filling by electrostatic gating.…

Mesoscale and Nanoscale Physics · Physics 2021-07-21 Nikhil Tilak , Xinyuan Lai , Shuang Wu , Zhenyuan Zhang , Mingyu Xu , Raquel de Almeida Ribeiro , Paul C Canfield , Eva Y. Andrei

We calculate the optical sum associated with the in-plane conductivity of a graphene bilayer. A bilayer asymmetry gap generated in a field-effect device can split apart valence and conduction bands, which otherwise would meet at two K…

Mesoscale and Nanoscale Physics · Physics 2008-04-08 L. Benfatto , S. G. Sharapov , J. P. Carbotte

The computation of the optical conductivity of strained and deformed graphene is discussed within the framework of quantum field theory in curved spaces. The analytical solutions of the Dirac equation in an arbitrary static background…

Materials Science · Physics 2015-12-01 W. de Paula , a. Chaves , O. Oliveira , T. Frederico

We calculate the perpendicular electrical conductivity in twisted three-dimensional graphite (rotationally stacked graphite pieces) by using the effective continuum model and the recursive Green's function method. In the low twist angle…

Mesoscale and Nanoscale Physics · Physics 2023-10-27 Tenta Tani , Takuto Kawakami , Mikito Koshino

We have surveyed the in-plane transport properties of the graphene twist bilayer using (i) a low-energy effective Hamiltonian for the underlying electronic structure, (ii) an isotropic elastic phonon model, and (iii) the linear Boltzmann…

Mesoscale and Nanoscale Physics · Physics 2016-12-21 N. Ray , M. Fleischmann , D. Weckbecker , S. Sharma , O. Pankratov , S. Shallcross

In this paper we systemically study the optical conductivity and density of states of disorded graphene beyond the Dirac cone approximation. The optical conductivity of graphene is computed by using the Kubo formula, within the framework of…

Mesoscale and Nanoscale Physics · Physics 2011-11-08 Shengjun Yuan , Rafael Roldán , Hans De Raedt , Mikhail I. Katsnelson

We show that the optical transparency of suspended graphene is defined by the fine structure constant, alpha, the parameter that describes coupling between light and relativistic electrons and is traditionally associated with quantum…

Mesoscale and Nanoscale Physics · Physics 2008-06-08 R. R. Nair , P. Blake , A. N. Grigorenko , K. S. Novoselov , T. J. Booth , T. Stauber , N. M. R. Peres , A. K. Geim

The phonon thermal transport properties of twisted bi-layer graphene are investigated using lattice dynamics and the Boltzmann transport equation. The thermal conductivities of 13.2 and 21.8 twisted configurations are 56% and 36% lower than…

Mesoscale and Nanoscale Physics · Physics 2023-11-07 Shahid Ahmed , Shadab Alam , Ankit Jain

We study the influence of different kinds of gaps in a quasiparticle spectrum on longitudinal and transverse optical conductivities of bilayer graphene. An exact analytical expression for magneto-optical conductivity is derived using a…

Strongly Correlated Electrons · Physics 2012-08-08 E. V. Gorbar , V. P. Gusynin , A. B. Kuzmenko , S. G. Sharapov

We develop a theory for density, disorder, and temperature dependent electrical conductivity of bilayer graphene in the presence of long-range charged impurity scattering as well as an additional short-range disorder of independent origin,…

Mesoscale and Nanoscale Physics · Physics 2010-04-21 S. Das Sarma , E. H. Hwang , E. Rossi

We theoretically study the optical absorption property of twisted bilayer graphenes with various stacking geometries, and demonstrate that the spectroscopic characteristics serve as a fingerprint to identify the rotation angle between two…

Mesoscale and Nanoscale Physics · Physics 2013-05-21 Pilkyung Moon , Mikito Koshino

We demonstrate that the plasmon frequency and Drude weight of the electron liquid in a doped graphene sheet are strongly renormalized by electron-electron interactions even in the long-wavelength limit. This effect is not captured by the…

Mesoscale and Nanoscale Physics · Physics 2011-07-19 Saeed H. Abedinpour , G. Vignale , A. Principi , Marco Polini , Wang-Kong Tse , A. H. MacDonald

The transport properties of a bilayer graphene are studied theoretically within a self-consistent Born approximation. The electronic spectrum is composed of $k$-linear dispersion in the low-energy region and $k$-square dispersion as in an…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Mikito Koshino , Tsuneya Ando

Understanding the mechanisms governing the optical activity of layered-stacked materials is crucial to the design of devices aimed at manipulating light at the nanoscale. Here, we show that both twisted and slid bilayer graphene are chiral…

Mesoscale and Nanoscale Physics · Physics 2020-11-30 V. Nam Do , H. Anh Le , V. Duy Nguyen , D. Bercioux

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