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The interband optical absorption of linearly polarised light by two-dimensional (2D) semimetals hosting tilted and anisotropic Dirac cones in the bandstructure is analysed theoretically. Super-critically tilted (type-II) Dirac cones are…

Mesoscale and Nanoscale Physics · Physics 2022-06-09 A. Wild , E. Mariani , M. E. Portnoi

The tunneling effect of two-dimensional Dirac fermions in a constant magnetic field is studied. This can be done by using the continuity equation at some points to determine the corresponding reflexion and transmission coefficients. For…

High Energy Physics - Theory · Physics 2011-04-28 El Bouazzaoui Choubabi , Mohamed El Bouziani , Ahmed Jellal

Gap opening at the Dirac point of the single-layer graphene with periodic scalar and vector potentials has been theoretically investigated under the continuum model. The symmetry analysis indicates that the two-fold degeneracy at the Dirac…

Mesoscale and Nanoscale Physics · Physics 2015-05-28 Xin Lin , Hailong Wang , Hui Pan , Huaizhe Xu

We present a two-band model based on periodic H\"uckel theory, which is capable of predicting the existence and position of Dirac cones in the first Brillouin zone of an infinite class of two-dimensional periodic carbon networks, obtained…

Mesoscale and Nanoscale Physics · Physics 2014-06-24 Willem Van den Heuvel , Alessandro Soncini

We show how strongly interacting two-dimensional Dirac fermions can be realized with ultracold atoms in a two-dimensional optical square lattice with an experimentally realistic, inherent gauge field, which breaks time-reversal and…

Quantum Gases · Physics 2015-05-13 Lih-King Lim , Achilleas Lazarides , Andreas Hemmerich , C. Morais Smith

We investigate Dirac fermions in the antifferomagnetic metallic state of iron-based superconduc- tors. Deriving an effective Hamiltonian for Dirac fermions, we reveal that there exist two Dirac cones carrying the same chirality, contrary to…

Superconductivity · Physics 2010-07-19 Takao Morinari , Eiji Kaneshita , Takami Tohyama

In the presence of axial magnetic fields that can be realized in deliberately buckled monolayer graphene, quasi-relativistic Dirac fermions may find themselves in a variety of broken symmetry phases even for weak interactions. Through a…

Mesoscale and Nanoscale Physics · Physics 2014-09-03 Bitan Roy , Jay D. Sau

We generalize a proposal by Sorensen et al. [Phys. Rev. Lett. 94, 086803 (2005)] for creating an artificial magnetic field in a cold atom system on a square optical lattice. This leads us to an effective lattice model with tunable spatially…

Quantum Gases · Physics 2018-12-13 Malcolm P. Kennett , Nazanin Komeilizadeh , Kamran Kaveh , Peter M. Smith

The adhesion of graphene on slightly lattice-mismatched surfaces, for instance of hexagonal boron nitride (hBN) or Ir(111), gives rise to a complex landscape of sublattice symmetry-breaking potentials for the Dirac fermions. Whereas a gap…

Materials Science · Physics 2015-06-03 Carmine Ortix , Liping Yang , Jeroen van den Brink

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…

Mesoscale and Nanoscale Physics · Physics 2023-10-10 Matheus S. M. de Sousa , Wei Chen

We study the electronic states of graphene in piecewise constant potentials using the continuum Dirac equation appropriate at low energies, and a transfer matrix method. For superlattice potentials, we identify patterns of induced Dirac…

Mesoscale and Nanoscale Physics · Physics 2015-05-18 D. P. Arovas , L. Brey , H. A. Fertig , Eun-Ah Kim , K. Ziegler

We study the electronic and transport properties of a graphene-based superlattice theoretically by using an effective Dirac equation. The superlattice consists of a periodic potential applied on a single-layer graphene deposited on a…

Mesoscale and Nanoscale Physics · Physics 2015-02-26 Jonas R. F. Lima

Inspired by the great development of graphene, more and more works have been conducted to seek new two-dimensional (2D) materials with Dirac cones. Although 2D Dirac materials possess many novel properties and physics, they are rare…

Mesoscale and Nanoscale Physics · Physics 2015-04-15 Jinying Wang , Shibin Deng , Zhongfan Liu , Zhirong Liu

Motivated by the realization of the Dirac point (DP) with a double-cone structure for optical field in the negative-zero-positive index metamaterial (NZPIM), the reflection, transmission, and Goos-H\"{a}nchen (GH) shifts inside the NZPIM…

Optics · Physics 2009-10-28 Xi Chen , Li-Gang Wang , Chun-Fang Li

The properties of Dirac electrons in a magnetic superlattice (SL) on graphene consisting of very high and thin (delta-function) barriers are investigated. We obtain the energy spectrum analytically and study the transmission through a…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 M. Ramezani Masir , P. Vasilopoulos , F. M. Peeters

This is a short review of two-dimensional Dirac fermions in graphene and similar systems such as boron nitride, quasi-2D organic salts $\alpha$-(BEDT-TTF)$_2$I$_3$, artificial graphene with cold atoms in optical lattices, etc. The emphasis…

Mesoscale and Nanoscale Physics · Physics 2013-06-04 Jean-Noel Fuchs

We study the transmission probability of Dirac fermions in graphene scattered by a triangular double barrier potential in the presence of an external magnetic field. Our system made of two triangular potential barrier regions separated by a…

Mesoscale and Nanoscale Physics · Physics 2015-11-24 Miloud Mekkaoui , Ahmed Jellal , Hocine Bahlouli

The three dimensional (3D) Dirac semimetal, which has been predicted theoretically, is a new electronic state of matter. It can be viewed as 3D generalization of graphene, with a unique electronic structure in which conduction and valence…

Mesoscale and Nanoscale Physics · Physics 2014-07-10 Sergey Borisenko , Quinn Gibson , Danil Evtushinsky , Volodymyr Zabolotnyy , Bernd Buechner , Robert J. Cava

The quantum Hall effect in graphene is regarded to be involving half-integer topological numbers associated with the massless Dirac particle, this is usually not apparent due to the doubling of the Dirac cones. Here we theoretically…

Mesoscale and Nanoscale Physics · Physics 2012-04-30 H Watanabe , Y Hatsugai , H Aoki

A quantum graph model for a single sheet of graphene is extended to bilayer and trilayer Bernal-stacked graphene; the spectra are characterized and the dispersion relations explicitly obtained; Dirac cones are then proven to be present only…

Mathematical Physics · Physics 2020-11-18 Cesar R. de Oliveira , Vinicius L. Rocha