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Using a combined Dynamical Mean Field Theory and Hartree (DMFT+H) calculation we study the transport and optical properties of the 8-band heavy fermion model for Twisted Bilayer Graphene (TBG) in the normal state. We find resistive states…

Strongly Correlated Electrons · Physics 2026-05-19 M. J. Calderón , A. Camjayi , A. Datta , E. Bascones

We calculate the finite-frequency conductivity of bilayer graphene with a relative twist between the layers. The low frequency response at zero doping shows a flat conductivity with value twice that of the monolayer case and at higher…

Mesoscale and Nanoscale Physics · Physics 2013-03-12 Calvin J. Tabert , Elisabeth J. Nicol

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

Using terahertz time-domain spectroscopy, the real part of optical conductivity [$\sigma_{1}(\omega)$] of twisted bilayer graphene was obtained at different temperatures (10 -- 300 K) in the frequency range 0.3 -- 3 THz. On top of a…

We study conductance across a twisted bilayer graphene coupled to single-layer graphene leads in two setups: a flake of graphene on top of an infinite graphene ribbon and two overlapping semi-infinite graphene ribbons. We find conductance…

Mesoscale and Nanoscale Physics · Physics 2020-07-30 Hadi Z. Olyaei , Bruno Amorim , Pedro Ribeiro , Eduardo V. Castro

When a bilayer of graphene is placed in a suitably configured field effect device, an asymmetry gap can be generated and the carrier concentration made different in each layer. This provides a tunable semiconducting gap, and the valence and…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 E. J. Nicol , J. P. Carbotte

The discoveries of numerous exciting phenomena in twisted bilayer graphene (TBG) are stimulating significant investigations on moir\'e structures that possess a tunable moir\'e potential. Optical response can provide insights into the…

A Drude-Boltzmann theory is used to calculate the transport properties of bilayer graphene. We find that for typical carrier densities accessible in graphene experiments, the dominant scattering mechanism is overscreened Coulomb impurities…

Mesoscale and Nanoscale Physics · Physics 2008-03-22 Shaffique Adam , S. Das Sarma

The mechanisms of optical activity and quantum transport of twisted bilayer graphene are studied. The formation of unique electron states in the bilayer systems is studied using an effective continuum model. Such states are shown to support…

Mesoscale and Nanoscale Physics · Physics 2022-05-26 S. Ta Ho , V. Nam Do

This study investigates optical activity and quantum transport in twisted bilayer graphene (TBG) systems, demonstrating that the former results from spatial dispersion effects. The transfer matrix method is used to solve the propagation of…

Mesoscale and Nanoscale Physics · Physics 2023-05-31 S. Ta Ho , V. Nam Do

We present a theory of the influence of band renormalization and excitonic electron-electron interaction effects on the optical conductivity $\sigma(\omega)$ of doped bilayer graphene. Using the Keldysh formalism, we derive a kinetic…

Mesoscale and Nanoscale Physics · Physics 2009-12-05 Wang-Kong Tse , A. H. MacDonald

We address the optical conductivity of undoped bilayer graphene in the presence of a finite bias voltage at finite temperature. The effects of gap parameter and stacking type on optical conductivity are discussed in the context of tight…

Strongly Correlated Electrons · Physics 2021-06-23 Bahram Maleki , Hamed Rezania

The optical conductivity of graphene strained uniaxially is studied within the Kubo-Greenwood formalism. Focusing on inter-band absorption, we analyze and quantify the breakdown of universal transparency in the visible region of the…

Mesoscale and Nanoscale Physics · Physics 2011-01-17 Vitor M. Pereira , R. M. Ribeiro , N. M. R. Peres , A. H. Castro Neto

In this article, we investigate the temperature and chemical potential dependence of the optical conductivity of graphene, within a field theoretical representation in the continuum approximation, arising from an underlying tight-binding…

Mesoscale and Nanoscale Physics · Physics 2020-01-08 Horacio Falomir , Enrique Muñoz , Marcelo Loewe , Renato Zamora

We theoretically study the band structure and optical conductivity of twisted bilayer graphene (TBG) near the magic angle considering the effects of lattice relaxation. We show that the optical conductivity spectrum is characterized by a…

Mesoscale and Nanoscale Physics · Physics 2021-02-03 Lu Wen , Zhiqiang Li , Yan He

The in-plane DC conductivity of twisted bilayer graphene (TBLG) is calculated using an expansion of the real-space Kubo-Bastin conductivity in terms of Chebyshev polynomials. We investigate within a tight-binding (TB) approach the transport…

Mesoscale and Nanoscale Physics · Physics 2018-03-28 M. Anđelković , L. Covaci , F. M. Peeters

We calculate the optical conductivity, $\sigma(\omega)$, in the normal state fullerene superconductors by self-consistently including the impurity scatterings, the electron-phonon and electron-electron Coulomb interactions. The finite…

Strongly Correlated Electrons · Physics 2009-10-31 Jung-Woo Yoo , Han-Yong Choi

The optical conductivities of graphene layers are strongly dependent on their stacking orders. Our first-principle calculations show that while the optical conductivities of single layer graphene (SLG) and bilayer graphene (BLG) with Bernal…

Materials Science · Physics 2010-11-04 Yingying Wang , Zhenhua Ni , Lei Liu , Yanhong Liu , Chunxiao Cong , Ting Yu , Xiaojun Wang , Dezhen Shen , Zexiang Shen

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

We report first-principles calculations of electron-phonon coupling in bilayer graphene and the corresponding contribution to carrier scattering. At the phonon $\Gamma$ point, electrons with energies less than 200 meV are scattered…

Mesoscale and Nanoscale Physics · Physics 2020-07-01 Yijun Ge , Timothy S. Fisher
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