The appearence of long-range correlations near the Dirac point of a Dirac-like spinor model with random vector potential is studied. These correlations originate from a spontaneously broken symmetry and their corresponding Goldstone modes. Using a strong-disorder expansion, correlation functions and matrix elements are analyzed and compared with results from a weak-disorder expansion. The local...

We investigate the conductivity σ of graphene nanoribbons with zigzag edges as a function of Fermi energy EF in the presence of the impurities with different potential range. The dependence of σ(EF ) displays four different types of behavior, classified to different regimes of length scales decided by the impurity potential range and its density. Particularly, low density of long range impuriti...

A tight-binding model with randomly fluctuating atomic positions is studied to discuss the effect of strong disorder in graphene. We employ a strong-disorder expansion for the transport quantities and find a diffusive behavior, where the conductivity is decreasing with increasing disorder. For sufficiently strong disorder the magnetic field drops out of the diffusion coefficient and the conduct...

Jean-Marie Poumirol,1 Alessandro Cresti,2,* Stephan Roche,3,4 Walter Escoffier,1 Michel Goiran,1 Xinran Wang,5 Xiaolin Li,5 Hongjie Dai,5 and Bertrand Raquet1 1Laboratoire National des Champs Magnétiques Intenses, INSA UPS CNRS, UPR 3228, Université de Toulouse, 143 avenue de Rangueil, 31400 Toulouse, France 2LETI, MINATEC, CEA, F38054 Grenoble, France 3INAC, SP2M, Lsim, CEA, 17 avenue des Mart...

We report an electron transport study of lithographically fabricated graphene nanoribbons (GNRs) of various widths and lengths. At the charge neutrality point, a length-independent transport gap forms whose size is inversely proportional to the GNR width. In this gap, electrons are localized, and charge transport exhibits a transition between thermally activated behavior at higher temperatures ...

Shengjun Yuan,1,* Rafael Roldán,2,† Antti-Pekka Jauho,3 and M. I. Katsnelson1 1Radboud University of Nijmegen, Institute for Molecules and Materials, Heijendaalseweg 135, 6525 AJ Nijmegen, The Netherlands 2Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco E28049 Madrid, Spain 3Center for Nanostructured Graphene (CNG), DTU Nanotech, Department of Microand Nanotechnology, Technical ...

In this work, we show that the maximum thermopower of few layers graphene (FLG) films could be greatly enhanced up to ∼700 μV/K after oxygen plasma treatment. The electrical conductivities of these plasma treated FLG films remain high, for example, ∼10(4) S/m, which results in power factors as high as ∼4.5 × 10(-3) W K(-2) m(-1). In comparison, the pristine FLG films show a maximum thermopower ...

The inhomogenous real-space electronic structure of gapless and gapped disordered bilayer graphene is calculated in the presence of quenched charge impurities. For gapped bilayer graphene, we find that for current experimental conditions the amplitude of the fluctuations of the screened disorder potential is of the order of (or often larger than) the intrinsic gap Δ induced by the application o...

In spite of its excellent electronic properties, the use of graphene in field-effect transistors is not practical at room temperature without modification of its intrinsically semimetallic nature to introduce a bandgap. Quantum confinement effects can create a bandgap in graphene nanoribbons, but existing nanoribbon fabrication methods are slow and often produce disordered edges that compromise...

We report the optical reflectivity and Raman scattering of few layer (L) graphene exposed to K and Rb vapors. Samples many tens of layers thick show the reflectivity and Raman spectra of the stage 1 bulk alkali intercalation compounds (GICs) KC(8) and RbC(8). However, these bulk optical and Raman properties only begin to appear in samples more than about 15 graphene layers thick. The 1 L to 4 L...