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We show that Coulomb drag in ultra-clean graphene double layers can be used for controlling the on/off ratio for current flow by tunning the external gate voltage. Hence, although graphene remains semi-metallic, the double layer graphene…

Mesoscale and Nanoscale Physics · Physics 2011-06-14 N. M. R. Peres , J. M. B. Lopes dos Santos , A. H. Castro Neto

Enhanced optical absorption in two-dimensional (2D) materials has recently moved into the focus of nanophotonics research. In this work, we present a gain-assisted method to achieve critical coupling and demonstrate the maximum absorption…

Optics · Physics 2021-03-02 Tingting Liu , Chaobiao Zhou , Shuyuan Xiao

We study the effect of Coulomb drag between two closely positioned graphene monolayers. In the limit of weak electron-electron interaction and small inter-layer spacing ($\mu_{1(2)}, T\ll v/d$) the drag is described by a universal function…

Mesoscale and Nanoscale Physics · Physics 2012-08-07 B. N. Narozhny , M. Titov , I. V. Gornyi , P. M. Ostrovsky

The effect of the long-range Coulomb interaction on the realization of the Kohn-Luttinger superconductivity in idealized monolayer doped graphene is studied. It is shown that the allowance for the Kohn-Luttinger renormalizations up to the…

Superconductivity · Physics 2016-02-03 M. Yu. Kagan , V. A. Mitskan , M. M. Korovushkin

The origin of superconductivity in magic-angle twisted bilayer graphene has been a subject of intense debate. While some experimental evidence indicated an unconventional pairing mechanism, efforts to tune the critical temperature by…

Mesoscale and Nanoscale Physics · Physics 2024-12-03 Julien Barrier , Liangtao Peng , Shuigang Xu , V. I. Fal'ko , K. Watanabe , T. Tanigushi , A. K. Geim , S. Adam , Alexey I. Berdyugin

The electronic quality of graphene has improved significantly over the past two decades, revealing novel phenomena. However, even state-of-the-art devices exhibit substantial spatial charge fluctuations originating from charged defects…

We study a model of strongly correlated electrons on the square lattice which exhibits charge frustration and quantum critical behavior. The potential is tuned to make the interactions supersymmetric. We establish a rigorous mathematical…

Strongly Correlated Electrons · Physics 2008-10-08 Liza Huijse , James Halverson , Paul Fendley , Kareljan Schoutens

We implement a self-consistent Hartree-Fock approximation based on a microscopic model in real space, which allows us to consider the interplay between the Hubbard and the extended Coulomb interaction in twisted bilayer graphene at the…

Mesoscale and Nanoscale Physics · Physics 2021-09-15 J. Gonzalez , T. Stauber

We analyze the Coulomb interacting problem in undoped graphene layers by using an excitonic variational ansatz. By minimizing the energy, we derive a gap equation which reproduces and extends known results. We show that a full treatment of…

Strongly Correlated Electrons · Physics 2011-05-27 J. Sabio , F. Sols , F. Guinea

The pseudo-magnetic field generated by mechanical strain in graphene can have dramatic consequences on the behavior of electrons and holes. Here we show that pseudo-magnetic field fluctuations present in crumpled graphene can induce…

The two-dimensional carbon allotrope graphene has recently attracted a lot of attention from researchers in the disciplines of Lattice Field Theory, Lattice QCD and Monte Carlo calculations. This interest has been prompted by several…

High Energy Physics - Lattice · Physics 2011-11-04 Timo A. Lähde , Joaquín E. Drut

We present an analytical investigation of the quasi-Coulomb impurity states in a narrow gapped armchair graphene nanoribbon (GNR) in the presence of a uniform external electric field directed parallel to the ribbon axis. The effect of the…

Mesoscale and Nanoscale Physics · Physics 2014-06-16 Boris S. Monzon , Peter Schmelcher

The Friedel sum rule is extended to deal with topological defects for the case of a graphene cone in the presence of an external Coulomb charge. The dependence in the way the number of states change due to both the topological defect as…

Mesoscale and Nanoscale Physics · Physics 2014-03-24 Baishali Chakraborty , Kumar S. Gupta , Siddhartha Sen

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

We show that the plasmon spectrum of an ordinary two-dimensional electron gas (2DEG) hosted in a GaAs heterostructure is significantly modified when a graphene sheet is placed on the surface of the semiconductor in close proximity to the…

Mesoscale and Nanoscale Physics · Physics 2012-08-21 Alessandro Principi , Matteo Carrega , Reza Asgari , Vittorio Pellegrini , Marco Polini

We analyze charging effects in graphene quantum dots. Using a simple model, we show that, when the Fermi level is far from the neutrality point, charging effects lead to a shift in the electrostatic potential and the dot shows standard…

Mesoscale and Nanoscale Physics · Physics 2008-02-06 B. Wunsch , T. Stauber , F. Guinea

We consider the 2D Hubbard model on the honeycomb lattice, as a model for a single layer graphene sheet in the presence of screened Coulomb interactions. At half filling and weak enough coupling, we compute the free energy, the ground state…

Mathematical Physics · Physics 2015-05-13 Alessandro Giuliani , Vieri Mastropietro

The effect of the intersite and interplane Coulomb interactions between the Dirac fermions on the formation of the Kohn-Luttinger superconductivity in bilayer doped graphene is studied disregarding the effects of the van der Waals potential…

Superconductivity · Physics 2016-02-08 M. Yu. Kagan , V. A. Mitskan , M. M. Korovushkin

We study the quantum many-body ground states of electrons on the half-filled honeycomb lattice with short- and long-ranged density-density interactions as a model for graphene. To this end, we employ the recently developed truncated-unity…

Strongly Correlated Electrons · Physics 2017-12-06 David Sánchez de la Peña , Julian Lichtenstein , Carsten Honerkamp , Michael M. Scherer

Relativistic quantum mechanics predicts that when the charge of a superheavy atomic nucleus surpasses a certain threshold, the resulting strong Coulomb field causes an unusual atomic collapse state; this state exhibits an electron wave…