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Filamentary structures identified in far-infrared observations of molecular clouds are typically found to have full-widths at half-maximum $\sim\!0.1$ pc. However, the physical explanation for this phenomenon is currently uncertain. We use…

Astrophysics of Galaxies · Physics 2021-10-13 F. D. Priestley , A. P. Whitworth

Various bandstructure engineering methods have been studied to improve the performance of graphitic transparent conductors; however none demonstrated an increase of optical transmittance in the visible range. Here we measure in situ optical…

Optical properties of graphene are explored by using the generalized tight-binding model. The main features of spectral structures, the form, frequency, number and intensity, are greatly enriched by the complex relationship among the…

Computational Physics · Physics 2016-07-20 Chiun-Yan Lin , Thi-Nga Do , Yao-Kung Huang , Ming-Fa Lin

We study conductance fluctuations (CF) and the sensitivity of the conductance to the motion of a single scatterer in two-dimensional massless Dirac systems. Our extensive numerical study finds limits to the predicted universal value of CF.…

Mesoscale and Nanoscale Physics · Physics 2013-04-29 Mario F. Borunda , Jesse Berezovsky , Robert M. Westervelt , Eric J. Heller

We study electron transport properties of a monoatomic graphite layer (graphene) with different types of disorder at half filling. We show that the transport properties of the system depend strongly on the symmetry of disorder. We find that…

Mesoscale and Nanoscale Physics · Physics 2007-10-04 P. M. Ostrovsky , I. V. Gornyi , A. D. Mirlin

Intrinsic rhombohedral graphene hosts an unusual low-energy electronic wavefunction, predominantly localized at its outer crystal faces with negligible presence in the bulk. Increasing the number of graphene layers amplifies the density of…

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 latest experiments have confirmed the theoretically expected universal value $\pi e^2/2h$ of the ac conductivity of graphene and have revealed departures of the quasiparticle dynamics from predictions for the Dirac fermions in idealized…

Strongly Correlated Electrons · Physics 2009-09-30 V. P. Gusynin , S. G. Sharapov , J. P. Carbotte

We present a model study to estimate the sensitivity of the optical absorption of multilayered graphene structure to the subnanometer interlayer separation. Starting from a transfer-matrix formalism we derive semi-analytical expressions for…

Optics · Physics 2022-11-28 Devashish Pandey , Sanshui Xiao , Martijn Wubs

Motivated by experiments confirming that the optical transparency of graphene is defined through the fine structure constant and that it could be fully explained within the relativistic Dirac fermions in 2D picture, in this article we…

Strongly Correlated Electrons · Physics 2018-11-28 Horacio Falomir , Marcelo Loewe , Enrique Muñoz , Alfredo Raya

We derive the nonlinear optical conductivity of an isotropic electron fluid at frequencies below the interparticle collision rate. In this regime, governed by hydrodynamics, the conductivity acquires a universal form at any temperature,…

Mesoscale and Nanoscale Physics · Physics 2018-02-22 Zhiyuan Sun , D. N. Basov , M. M. Fogler

A universal exponential factor, $\gamma_{c}=\pi/2$, is disclosed for the dimensional crossover of few-layer graphene (FLG) from two-dimensional graphene to three-dimensional graphite. $\gamma_{c}$ is found by analyzing available…

Materials Science · Physics 2011-08-31 Jin-Wu Jiang , Jian-Sheng Wang

We study the inter-valley scattering induced by the Coulomb repulsion as a purely electronic mechanism for the origin of superconductivity in few layers of graphene. The pairing is strongly favored by the presence of van Hove singularities…

Strongly Correlated Electrons · Physics 2023-01-31 Tommaso Cea

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

A universal adjacency matrix of a graph $G$ with adjacency matrix $A$ is any matrix of the form $U = \alpha A + \beta I + \gamma J + \delta D$ with $\alpha \neq 0$, where $I$ is the identity matrix, $J$ is the all-ones matrix and $D$ is the…

Combinatorics · Mathematics 2020-04-07 Willem H. Haemers , Mohammad Reza Oboudi

Graphene is a 2D material with appealing electronic and optoelectronic properties. It is a zero-bandgap material with valence and conduction bands meeting in a single point (Dirac point) in the momentum space. Its conductivity can be…

Applied Physics · Physics 2020-03-10 V. Sorianello , G. Contestabile , M. Romagnoli

We present a general formulation to calculate the dynamic optical conductivity, beyond the linear response regime, of any electronic system whose quasiparticle dispersion is described by a two band model. Our phenomenological model is based…

Mesoscale and Nanoscale Physics · Physics 2017-04-19 Ashutosh Singh , Tuhina Satpati , Kirill I. Bolotin , Saikat Ghosh , Amit Agarwal

We present a calculation of the low frequency optical conductivity of a superconductor in the presence of quenched inhomogeneity in both the superfluid and normal fluid densities. We find that inhomogeneity in the superfluid density…

Superconductivity · Physics 2009-11-07 Joseph Orenstein

We calculate the average conductivity sigma (omega) of interacting electrons in one dimension in the presence of a long-range random potential (forward scattering disorder). Taking the curvature of the energy dispersion into account, we…

Strongly Correlated Electrons · Physics 2009-10-31 Peter Kopietz , Guillermo E. Castilla

We consider the dynamics of charge carriers in single-layer graphene that are subject to random temporal fluctuations of their mass gap. The optical conductivity is calculated by incorporating the quantum-stochastic time evolution into the…

Mesoscale and Nanoscale Physics · Physics 2015-05-27 J. Z. Bernád