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A computational method is developed whereby the reflectivity of low-energy electrons from a surface can be obtained from a first-principles solution of the electronic structure of the system. The method is applied to multilayer graphene.…

Mesoscale and Nanoscale Physics · Physics 2014-01-21 R. M. Feenstra , M. Widom

We devise a supersymmetry-based method for the construction of zero-energy states in graphene. Our method is applied to a two-dimensional massless Dirac equation with a hyperbolic scalar potential. We determine supersymmetric partners of…

Mathematical Physics · Physics 2017-09-13 Axel Schulze Halberg , Pinaki Roy

Among many remarkable qualities of graphene, its electronic properties attract particular interest due to a massless chiral character of charge carriers, which leads to such unusual phenomena as metallic conductivity in the limit of no…

Mesoscale and Nanoscale Physics · Physics 2011-04-07 F. Guinea , M. I. Katsnelson , A. K. Geim

We study the magnetic properties of nanometer-sized graphene structures with triangular and hexagonal shapes terminated by zig-zag edges. We discuss how the shape of the island, the imbalance in the number of atoms belonging to the two…

Mesoscale and Nanoscale Physics · Physics 2007-10-30 J. Fernandez-Rossier , J. J. Palacios

We investigate the ground-state properties of triangular graphene nanoflakes with zigzag edge configurations. The description of zero-dimensional nanostructures requires accurate many-body techniques since the widely used density-functional…

Strongly Correlated Electrons · Physics 2018-01-24 I. Hagymasi , O. Legeza

Anomalous quantum Hall effects in single-layer and bilayer graphene are related with nontrivial topological properties of electron states (Berry phases $\pi$ and 2$\pi$, respectively). It was known that the Atiyah-Singer index theorem…

Mesoscale and Nanoscale Physics · Physics 2008-09-17 M. I. Katsnelson , M. F. Prokhorova

We investigate theoretically the magnetic levels and optical properties of zigzag- and armchair-edged hexagonal graphene quantum dots (GQDs) utilizing the tight-binding method. A new bound edge state at zero energy appears for the zigzag…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Z. Z. Zhang , Kai Chang , F. M. Peeters

In this article, we study zigzag graphene nanoribbons with edges reconstructed with Stone-Wales defects, by means of an empirical (first-neighbor) tight-binding method, with parameters determined by ab-initio calculations of very narrow…

We show that the twisted graphene bilayer can reveal unusual topological properties at low energies, as a consequence of a Dirac-point splitting. These features rely on a symmetry analysis of the electron hopping between the two layers of…

Mesoscale and Nanoscale Physics · Physics 2011-07-21 R. de Gail , M. O. Goerbig , F. Guinea , G. Montambaux , A. H. Castro Neto

We present efficient angle-dependent low-energy Hamiltonians to describe the properties of the twisted bilayer graphene (tBLG) heterostructure, based on {\it ab initio} calculations of mechanical relxation and electronic structure. The…

Mesoscale and Nanoscale Physics · Physics 2019-08-02 Shiang Fang , Stephen Carr , Ziyan Zhu , Daniel Massatt , Efthimios Kaxiras

The nature of correlated states in twisted bilayer graphene (TBG) at the magic angle has received intense attention in recent years. We present a numerical study of an interacting Bistritzer-MacDonald (IBM) model of TBG using a suite of…

Systematic tight-binding investigations of the electronic spectra (as a function of the magnetic field) are presented for trigonal graphene nanoflakes with reconstructed zigzag edges, where a succession of pentagons and heptagons, that is…

Mesoscale and Nanoscale Physics · Physics 2012-10-29 Igor Romanovsky , Constantine Yannouleas , Uzi Landman

We use density functional theory to determine the equilibrium shape of graphene flakes, through the calculation of the edge orientation dependence of the edge energy and edge stress of graphene nanoribbons. The edge energy is a nearly…

Mesoscale and Nanoscale Physics · Physics 2011-08-08 Chee Kwan Gan , David J. Srolovitz

We study the energetic stability and the local electronic structure of the general twisted trilayer graphene (TTG) with the top and bottom layers rotated with respect to the middle layer respectively by $\theta$ and $\theta'$. Approximate…

Mesoscale and Nanoscale Physics · Physics 2022-09-14 Xianqing Lin , Cheng Li , Kelu Su , Jun Ni

We develop a general theoretical framework based on $Z$-classification to count the number of topological bound states at a junction of chiral-symmetric one-dimensional systems. The formulation applies to general multiway junctions composed…

Mesoscale and Nanoscale Physics · Physics 2020-06-24 Gen Tamaki , Takuto Kawakami , Mikito Koshino

We generalize the known solution of the Schr\"odinger equation, describing a particle confined to a triangular area, for a triangular graphene quantum dot with armchair-type boundaries. The quantization conditions, wave functions, and the…

Mesoscale and Nanoscale Physics · Physics 2010-11-11 A. V. Rozhkov , Franco Nori

We investigate the reflectionlessness and invisibility properties in the transverse electric (TE) mode solution of a linear homogeneous optical system which comprises the $\mathcal{PT}$-symmetric structures covered by graphene sheets. We…

Optics · Physics 2018-01-11 Mustafa Sarisaman , Murat Tas

The dominance of Coulomb interactions over kinetic energy of electrons in narrow, non-trivial moir\'{e} bands of magic-angle twisted bilayer graphene (TBG) gives rise to a variety of correlated phases such as correlated insulators,…

In this paper, the electronic properties of 30{\deg} twisted double bilayer graphene, which loses the translational symmetry due to the incommensurate twist angle, are studied by means of the tight-binding approximation. We demonstrate the…

Materials Science · Physics 2020-09-14 Guodong Yu , Zewen Wu , Zhen Zhan , Mikhail I. Katsnelson , Shengjun Yuan

We develop a suitable technique to design zero-energy graphene models with radial electrostatic potentials capable of achieving electrostatic confinement. Using the Gaussian law for electrostatics, we derive the charge density associated…

Mesoscale and Nanoscale Physics · Physics 2025-10-31 Francisco Correa , Luis Inzunza , Vít Jakubský