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We investigate the transmissions of fermions through gapped graphene structures by employing a combination of double barrier tilting and a time-oscillating potential. The latter introduces additional sidebands into the transmission…

Mesoscale and Nanoscale Physics · Physics 2024-05-28 Miloud Mekkaoui , Ahmed Jellal , Abderrahim El Mouhafid

Whereas massless Dirac fermions in monolayer graphene exhibit Klein tunneling when passing through a potential barrier upon normal incidence, such a barrier totally reflects massive Dirac fermions in bilayer graphene due to difference in…

Mesoscale and Nanoscale Physics · Physics 2012-04-09 Neetu Agrawal , Sameer Grover , Sankalpa Ghosh , Manish Sharma

We study the tunneling of Dirac fermions in graphene through a double barrier potential allowing the carriers to have an effective mass inside the barrier as generated by a lattice miss-match with the boron nitride substrate. The…

Mesoscale and Nanoscale Physics · Physics 2016-05-06 Hocine Bahlouli , El Bouazzaoui Choubabi , Ahmed Jellal , Miloud Mekkaoui

Gap opening in graphene is usually discussed in terms of a semiconducting-like spectrum, where the appearance of a finite gap at the Dirac point is accompanied by a finite mass for the fermions. In this Letter we propose a gap scenario from…

Mesoscale and Nanoscale Physics · Physics 2008-10-03 L. Benfatto , E. Cappelluti

The strong Coulomb interaction between massless Dirac fermions can drive a semimetal-insulator transition in single-layer graphene by dynamically generating an excitonic fermion gap. There is a critical interaction strength $\lambda_c$ that…

Strongly Correlated Electrons · Physics 2015-03-13 Wei Li , Guo-Zhu Liu

The list of textbook tunneling formulas is extended by deriving exact expressions for the transmission coefficient in graphene ribbons with armchair edges and the step-like and barrier-like profiles of site energies along the ribbon. These…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 Yuriy Klymenko , Lyuba Malysheva , Alexander Onipko

Extended defects in graphene, such as linear edges, break the translational invariance and can also have an impact on the symmetries specific to massless Dirac-like quasiparticles in this material. The paper examines the consequences of a…

Mesoscale and Nanoscale Physics · Physics 2009-05-25 Grigory Tkachov , Martina Hentschel

Motivated by the physics of graphene, we consider a model of N species of 2+1 dimensional four-component massless Dirac fermions interacting through a 3D instantaneous Coulomb interaction. We show that in the limit of infinitely strong…

Strongly Correlated Electrons · Physics 2007-07-11 D. T. Son

The energy spectrum of graphene sheet with a single barrier structure having a time periodic oscillating height and subjected to magnetic field is analyzed. The corresponding transmission is studied as function of the obtained energy and…

Mesoscale and Nanoscale Physics · Physics 2015-06-18 Ahmed Jellal , Miloud Mekkaoui , El Bouazzaoui Choubabi , Hocine Bahlouli

Massless Dirac fermions in graphene provide unprecedented opportunities to realize the Klein paradox, which is one of the most exotic and striking properties of relativistic particles. In the seminal theoretical work [Katsnelson et al.,…

Mesoscale and Nanoscale Physics · Physics 2017-05-17 Ke-Ke Bai , Jia-Bin Qiao , Hua Jiang , Haiwen Liu , Lin He

We calculate the minimal energy path over the sphaleron barrier in the pre\-sen\-ce of fermions, assuming that the fermions of a doublet are degenerate in mass. This allows for spherically symmetric ans\"atze for the fields, when the mixing…

High Energy Physics - Phenomenology · Physics 2009-10-22 Guido Nolte , Jutta Kunz

Massless 2+1D Dirac fermions arise in a variety of systems from graphene to the surfaces of topological insulators, where generating a mass is typically associated with breaking a symmetry. However, with strong interactions, a symmetric…

Strongly Correlated Electrons · Physics 2018-02-21 Yi-Zhuang You , Yin-Chen He , Cenke Xu , Ashvin Vishwanath

The honeycomb lattice of graphene is a unique two-dimensional (2D) system where the quantum mechanics of electrons is equivalent to that of relativistic Dirac fermions. Novel nanometer-scale behavior in this material, including electronic…

Mesoscale and Nanoscale Physics · Physics 2009-05-29 Yuanbo Zhang , Victor W. Brar , Feng Wang , Caglar Girit , Yossi Yayon , Melissa Panlasigui , Alex Zettl , Michael F. Crommie

Graphene plasmons have recently attracted a great deal of attention because of their tunability, long lifetime, and high degree of field confinement in the vertical direction. Nearby metal gates have been shown to modify the graphene…

Mesoscale and Nanoscale Physics · Physics 2018-08-01 Alessandro Principi , Erik van Loon , Marco Polini , Mikhail I. Katsnelson

When a single-layer graphene sheet is contacted with metallic electrodes, tunnel barriers are formed as a result of the doping of graphene by the metal in the contact region. If the Fermi energy level is modulated by a gate voltage, the…

Mesoscale and Nanoscale Physics · Physics 2021-10-11 Gheorghe Sorin Paraoanu

Mechanism of transient population inversion in graphene with multi-splitted (interdigitated) top-gate and grounded back gate is suggested and examined for the mid-infrared (mid-IR) spectral region. Efficient stimulated emission after fast…

Mesoscale and Nanoscale Physics · Physics 2015-06-16 A. Satou , F. T. Vasko , T. Otsuji , V. V. Mitin

Using a composite fermion picture, we study the lateral transport between two two-dimensional electron gases, at filling factor 1/2, separated by a potential barrier. In the mean field approximation, composite fermions far from the barrier…

Condensed Matter · Physics 2009-10-28 L. Brey , C. Tejedor

We study quasi-particle transmission through an $n $-$p$ junction in a graphene irradiated by an electromagnetic field (EF). In the absence of EF the electronic spectrum of undoped graphene is gapless, and one may expect the perfect…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 M. V. Fistul , K. B. Efetov

We study the tunneling of chiral electrons in graphene through a region where the electronic spectrum changes from the usual linear dispersion to a hyperbolic dispersion, due to the presence of a gap. It is shown that contrary to the…

Mesoscale and Nanoscale Physics · Physics 2008-07-09 J. Viana Gomes , N. M. R. Peres

It is highly desirable to integrate graphene into existing semiconductor technology, where the combined system is thermodynamically stable yet maintain a Dirac cone at the Fermi level. Firstprinciples calculations reveal that a certain…

Mesoscale and Nanoscale Physics · Physics 2012-11-16 Yuanchang Li , Pengcheng Chen , Gang Zhou , Jia Li , Jian Wu , Bing-Lin Gu , S. B. Zhang , Wenhui Duan
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