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We study narrow zigzag graphene nanoribbons (ZGNRs), employing density functional theory (DFT) simulations and the tight-binding (TB) method. The main result of these calculations is the braiding of the conduction and valence bands,…

Mesoscale and Nanoscale Physics · Physics 2018-07-25 J. H. Correa , A. Pezo , M. S. Figueira

An analysis of the electron localization properties in doped graphene is performed by doing a numerical multifractal analysis. By obtaining the singularity spectrum of a tight-binding model, it is found that the electron wave functions…

Disordered Systems and Neural Networks · Physics 2013-07-01 J. E. Barrios-Vargas , Gerardo G. Naumis

We study distributions of the ratios of level spacings of a rectangular and an Africa-shaped superconducting microwave resonator containing circular scatterers on a triangular grid, so-called Dirac billiards (DBs). The high-precision…

Chaotic Dynamics · Physics 2016-01-27 B. Dietz , T. Klaus , M. Miski-Oglu , A. Richter , M. Wunderle , C. Bouazza

We examine the 1/N expansion, where N is the number of two-component Dirac fermions, for Coulomb interactions in graphene with a gap of magnitude $\Delta = 2 m$. We find that for $N\alpha\gg1$, where $\alpha$ is graphene's "fine structure…

Mesoscale and Nanoscale Physics · Physics 2022-03-07 Valeri N. Kotov , Bruno Uchoa , A. H. Castro Neto

The discovery of the Dirac electron dispersion in graphene led to the question of the Dirac cone stability with respect to interactions. Coulomb interactions between electrons were shown to induce a logarithmic renormalization of the Dirac…

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.…

Mesoscale and Nanoscale Physics · Physics 2008-09-04 K. Ziegler

We analyze the nature of the single particle states, away from the Dirac point, in the presence of long-range charge impurities in a tight-binding model for electrons on a two-dimensional honeycomb lattice which is of direct relevance for…

Mesoscale and Nanoscale Physics · Physics 2016-06-22 Sabyasachi Nag , Arti Garg , T. V. Ramakrishnan

We study the band structure of graphene's Dirac-Weyl quasi-particles in a one-dimensional magnetic superlattice formed by a periodic sequence of alternating magnetic barriers. The spectrum and the nature of the states strongly depend on the…

Mesoscale and Nanoscale Physics · Physics 2015-03-17 Luca Dell'Anna , Alessandro De Martino

A topological Dirac semimetal is a novel state of quantum matter which has recently attracted much attention as an apparent 3D version of graphene. In this paper, we report critically important results on the electronic structure of the 3D…

Three dimensional (3D) topological Dirac materials are under intensive study recently. The layered compound ZrTe$_5$ has been suggested to be one of them by transport and ARPES experiments. Here, we perform infrared reflectivity measurement…

Materials Science · Physics 2015-08-12 R. Y. Chen , S. J. Zhang , J. A. Schneeloch , C. Zhang , Q. Li , G. D. Gu , N. L. Wang

Thermodynamics coupled with quantum features on electron and hole dynamics in Dirac materials is quite interesting and crucial for real device applications. The correlation between the formation of electron-hole puddles in nearer to the…

Mesoscale and Nanoscale Physics · Physics 2026-02-27 Karuppuchamy Navamani

We investigate the emergence of extra Dirac points in the electronic structure of a periodically spaced barrier system, i.e., a superlattice, on single-layer graphene, using a Dirac-type Hamiltonian. Using square barriers allows us to find…

Mesoscale and Nanoscale Physics · Physics 2015-05-18 M. Barbier , P. Vasilopoulos , F. M. Peeters

The moir\'e superlattice induced in graphene by the hexagonal boron nitride substrate modifies strongly the bandstructure of graphene, which manifests itself by the appearance of new Dirac points, accompanied by van Hove singularities. In…

Mesoscale and Nanoscale Physics · Physics 2018-10-03 D. I. Indolese , R. Delagrange , P. Makk , J. R. Wallbank , K. Wanatabe , T. Taniguchi , C. Schönenberger

The electronic structure of a crystalline solid is largely determined by its lattice structure. Recent advances in van der Waals solids, artificial crystals with controlled stacking of two-dimensional (2D) atomic films, have enabled the…

We report on numerical study of the Dirac fermions in partially filled N=3 Landau level (LL) in graphene. At half-filling, the equal-time density-density correlation function displays sharp peaks at nonzero wavevectors $\pm {\bf q^{*}}$.…

Strongly Correlated Electrons · Physics 2008-03-31 Hao Wang , D. N. Sheng , L. Sheng , F. D. M. Haldane

We consider the electronic structure of a slightly twisted graphene bilayer and show the coexistence of van Hove singularities (VHSs) and superlattice Dirac points in a continuum approximation. The graphene-on-graphene moir\'e pattern gives…

Mesoscale and Nanoscale Physics · Physics 2013-04-19 Zhao-Dong Chu , Wen-Yu He , Lin He

We analyze the energy spectrum of graphene in the presence of spin-orbit coupling and a unidirectionally periodic Zeeman field, focusing on the stability and location of Dirac points it may support. It is found that the Dirac points at the…

Mesoscale and Nanoscale Physics · Physics 2016-08-24 Luis Brey , A. R. Carvalho , H. A. Fertig

In many of three-dimensional metals with the inversion symmetry and a weak spin-orbit interaction, Dirac points of the electron energy spectrum form band-contact lines in the Brillouin zones of these crystals, and electron topological…

Mesoscale and Nanoscale Physics · Physics 2014-10-28 G. P. Mikitik , Yu. V. Sharlai

The electronic properties of non-interacting particles moving on a two-dimensional bricklayer lattice are investigated numerically. In particular, the influence of disorder in form of a spatially varying random magnetic flux is studied. In…

Disordered Systems and Neural Networks · Physics 2009-12-22 L. Schweitzer

Lateral superlattices have attracted major interest as this may allow one to modify spectra of two dimensional electron systems and, ultimately, create materials with tailored electronic properties. Previously, it proved difficult to…