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Dirac fermions interacting with a cylindrically symmetric quantum dot potential created in single and bilayer graphene are not confined but form quasi-bound states. The broadening of these quasi-bound states (i. e. the inverse of their…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 A. Matulis , F. M. Peeters

We analyze the scattering sector of the Hamiltonians for both gapless and gapped graphene in the presence of a charge impurity using the 2D Dirac equation, which is applicable in the long wavelength limit. We show that for certain range of…

Mesoscale and Nanoscale Physics · Physics 2011-04-07 Kumar S. Gupta , Andjelo Samsarov , Siddhartha Sen

Bound and resonance electronic states in impure graphene are studied. Short-range perturbations for defects and impurities of the types "local chemical potential" and "local gap" are taken into account. Zero gap and non-zero gap kinds of…

Mesoscale and Nanoscale Physics · Physics 2009-05-25 Natalie E. Firsova , Sergey A. Ktitorov , Philip A. Pogorelov

The electronic states of an electrostatically confined cylindrical graphene quantum dot and the electric transport through this device are studied theoretically within the continuum Dirac-equation approximation and compared with numerical…

Mesoscale and Nanoscale Physics · Physics 2011-08-12 G. Pal , W. Apel , L. Schweitzer

We study the localization properties of the wavefunctions in graphene flakes with short range disorder, via the numerical calculation of the Inverse Participation Ratio($IPR$) and it scaling which provides the fractal dimension $D_{2}$. We…

Mesoscale and Nanoscale Physics · Physics 2014-02-21 Ioannis Kleftogiannis , Ilias Amanatidis

We study the Friedel oscillations induced by a localized impurity in anisotropic graphene. We focus on the limit when the two inequivalent Dirac points merge. We find that in this limit the Friedel oscillations manifest very peculiar…

Mesoscale and Nanoscale Physics · Physics 2016-06-07 Clément Dutreix , Liviu Bilteanu , Anu Jagannathan , Cristina Bena

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

The present article discusses magnetic confinement of the Dirac excitations in graphene in presence of inhomogeneous magnetic fields. In the first case a magnetic field directed along the z axis whose magnitude is proportional to $1/r$ is…

Mesoscale and Nanoscale Physics · Physics 2015-05-30 Pratim Roy , Tarun Kanti Ghosh , Kaushik Bhattacharya

Two-dimensional carbon, or graphene, is a semi-metal that presents unusual low-energy electronic excitations described in terms of Dirac fermions. We analyze in a self-consistent way the effects of localized (impurities or vacancies) and…

Strongly Correlated Electrons · Physics 2009-11-11 N. M. R. Peres , F. Guinea , A. H. Castro Neto

The present study explores the edge states in a finite-width graphene ribbon and a semi-infinite geometry subject to a perpendicular magnetic field and an in-plane electric field, applied perpendicular to a zigzag edge. To accomplish this,…

Mesoscale and Nanoscale Physics · Physics 2023-04-17 A. A. Herasymchuk , S. G. Sharapov , V. P. Gusynin

We explore the gapped graphene structure in the two-dimensional plane in the presence of the Rosen-Morse potential and an external uniform magnetic field. In order to describe the corresponding structure, we consider the propagation of…

Mesoscale and Nanoscale Physics · Physics 2024-09-04 A. Kalani , Alireza Amani , M. A. Ramzanpour

We investigate the effects of the curved geometry on a massless relativistic electron constrained to a graphene strip with a Moebius strip shape. The anisotropic and parity-violating geometry of the Moebius band produces a geometric…

Mesoscale and Nanoscale Physics · Physics 2023-09-25 L. N. Monteiro , J. E. G. Silva , C. A. S. Almeida

We study the combined effect of a conical topological defect and a Coulomb charge impurity on the dynamics of Dirac fermions in gapped graphene. Beyond a certain strength of the Coulomb charge, quantum instability sets in, which demarcates…

High Energy Physics - Theory · Physics 2015-06-05 Baishali Chakraborty , Kumar S. Gupta , Siddhartha Sen

We investigate new properties of the Dirac electrons in the finite graphene sample under perpendicular magnetic field that emerge when an in-plane electric bias is also applied. The numerical analysis of the Hofstadter spectrum and of the…

Mesoscale and Nanoscale Physics · Physics 2015-06-23 B. Ostahie , M. Nita , A. Aldea

In neutral graphene dots the Fermi level coincides with the Dirac points. We have investigated in the presence of a magnetic field several unusual properties of single electron states near the Fermi level of such a rectangular-shaped…

Mesoscale and Nanoscale Physics · Physics 2010-02-24 S. C. Kim , P. S. Park , S. -R. Eric Yang

The electronic structure in the vicinity of the 1-heptagonal and 1-pentagonal defects in the carbon graphene plane is investigated. Using a continuum gauge field-theory model the local density of states around the Fermi energy is calculated…

Mesoscale and Nanoscale Physics · Physics 2011-12-06 J. Smotlacha , R. Pincak , M. Pudlak

We study the influence of pentagons, dislocations and other topological defects breaking the sublattice symmetry on the magnetic properties of a graphene lattice in a Hartree Fock mean field scheme. The ground state of the system with a…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 María P. López-Sancho , Fernando de Juan , María A. H. Vozmediano

We have investigated a new feature of impurity cyclotron resonances common to various localized potentials of graphene. A localized potential can interact with a magnetic field in an unexpected way in graphene. It can lead to formation of…

Mesoscale and Nanoscale Physics · Physics 2014-07-25 S. C. Kim , S. -R. Eric Yang , A. H. MacDonald

The behavior of electrons in strained graphene is usually described using effective pseudomagnetic fields in a Dirac equation. Here we consider the particular case of a spatially constant strain. Our results indicate that lattice…

Mesoscale and Nanoscale Physics · Physics 2013-09-10 M. Oliva-Leyva , G. G. Naumis

We study the properties of graphene wormholes in which a short nanotube acts as a bridge between two graphene sheets, where the honeycomb carbon lattice is curved from the presence of 12 heptagonal defects. By taking the nanotube bridge…

Mesoscale and Nanoscale Physics · Physics 2009-11-09 J. Gonzalez , J. Herrero