Related papers: Universal Dynamic Conductivity and Quantized Visib…
Graphene and other two-dimensional materials display remarkable optical properties, including a simple light transparency of $T \approx 1 - \pi \alpha$ for light in the visible region. Most theoretical rationalizations of this "universal"…
Reflectance and transmittance of graphene in the optical region are analyzed as a function of frequency, temperature, and carrier density. We show that the optical graphene properties are determined by the direct interband electron…
Optical reflectivity and transmission measurements over photon energies between 0.2 and 1.2 eV were performed on single-crystal graphene samples on a transparent SiO2 substrate. For photon energies above 0.5 eV, graphene yielded a…
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…
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…
The opacity of graphene is known to be approximately given by the fine-structure constant $\alpha$ times $\pi$. We point out the fact that the opacity is roughly independent of the frequency and polarization of the light can be attributed…
The observed 97.7% optical transparency of graphene has been linked to the value 1/137 of the fine structure constant, by using results for noninteracting Dirac fermions. The agreement in three significant figures requires an explanation…
We calculate the optical (cutoff >> frequency >> temperature) conductivity in clean graphene in the ultimate low-energy regime, when retardation effects of the electromagnetic interaction become important and when the full Lorentz symmetry…
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…
The independence of the dynamic conductivity of intrinsic graphene of frequency takes its origin in the compensation of the vanishing density of states by the diverging matrix element of the corresponding interband transition. The…
We find experimentally that the optical sheet conductance of graphite per graphene layer is very close to $(\pi/2)e^2/h$, which is the theoretically expected value of dynamical conductance of isolated monolayer graphene. Our calculations…
Minimal conductivity of a single undoped graphene layer is known to be of the order of the conductance quantum, independent of the electron velocity. We show that this universality does not survive electron-electron interaction which…
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…
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…
We show that for graphene with any finite difference in the on-site energy between the two sub-lattices ($\Delta$), The optical absorption edge is determined by the $\Delta$. The universal conductance will be broken and the conductance near…
The inter-band optical absorption in graphene characterized by its fine-structure constant has a universal value of 2.3\% independent of the material parameters. However, for several graphene-based photonic applications, enhanced optical…
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…
Conductivity of a disorder-free intrinsic graphene is studied to the first order in the long-range Coulomb interaction and is found to be \sigma=\sigma_0(1+0.01 g), where 'g' is the dimensionless ("fine structure") coupling constant. The…
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…
In the present paper, using Pseudo-Quantum Electrodynamics to describe the interaction between electrons in graphene, we investigate the longitudinal and optical conductivities of a neutral graphene sheet near a grounded perfectly…