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The relativistic-like behavior of electrons in graphene significantly influences the interaction properties of these electrons in a quantizing magnetic field, resulting in more stable fractional quantum Hall effect states as compared to…

Mesoscale and Nanoscale Physics · Physics 2015-06-15 Tapash Chakraborty , Vadim Apalkov

Tunnelling of electrons in graphene-based junctions is studied theoretically. Graphene is assumed to be deposited either directly on a ferromagnetic insulator or on a few atomic layers of boron nitride which separate graphene from a…

Mesoscale and Nanoscale Physics · Physics 2019-05-01 Jędrzej Tepper , Józef Barnaś

When an electron is confined to a triangular atomic thick layer of graphene [1-5] with zig-zag edges, its energy spectrum collapses to a shell of degenerate states at the Fermi level (Dirac point) [6-9]. The degeneracy is proportional to…

Materials Science · Physics 2013-05-29 A. D. Guclu , P. Potasz , O. Voznyy , M. Korkusinski , P. Hawrylak

The compressibility of a two-dimensional electron system with spin in a spatially correlated random potential and a quantizing magnetic field is investigated. Electron-electron interaction is treated with the Hartree-Fock method. Numerical…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Alexander Struck , Bernhard Kramer

We review the basic aspects of electrons in graphene (two-dimensional graphite) exposed to a strong perpendicular magnetic field. One of its most salient features is the relativistic quantum Hall effect the observation of which has been the…

Mesoscale and Nanoscale Physics · Physics 2011-11-24 M. O. Goerbig

We report experimental observation of the reentrant integer quantum Hall effect in graphene, appearing in the N$=$2 Landau level. Similar to high-mobility GaAs/AlGaAs heterostructures, the effect is due to a competition between…

Mesoscale and Nanoscale Physics · Physics 2019-01-23 Shaowen Chen , Rebeca Ribeiro-Palau , Kang Yang , Kenji Watanabe , Takashi Taniguchi , James Hone , Mark O. Goerbig , Cory R. Dean

Recent reports of spin-orbit coupling enhancement in chemically modified graphene have opened doors to studies of the spin Hall effect with massless chiral fermions. Here, we theoretically investigate the interaction and impurity density…

Mesoscale and Nanoscale Physics · Physics 2016-11-15 Mirco Milletari , Aires Ferreira

An exact mapping of the tight-binding Hamiltonian for a graphene's nanoribbon under any armchair uniaxial strain into an effective one-dimensional system is presented. As an application, for a periodic modulation we have found a gap opening…

Mesoscale and Nanoscale Physics · Physics 2015-04-27 Pedro Roman-Taboada , Gerardo G. Naumis

Graphene is a unique two-dimensional material with rich new physics and great promise for applications in electronic devices. Physical phenomena such as the half-integer quantum Hall effect and high carrier mobility are critically dependent…

Electrons moving through a spatially periodic lattice potential develop a quantized energy spectrum consisting of discrete Bloch bands. In two dimensions, electrons moving through a magnetic field also develop a quantized energy spectrum,…

Mesoscale and Nanoscale Physics · Physics 2013-05-17 C. R. Dean , L. Wang , P. Maher , C. Forsythe , F. Ghahari , Y. Gao , J. Katoch , M. Ishigami , P. Moon , M. Koshino , T. Taniguchi , K. Watanabe , K. L. Shepard , J. Hone , P. Kim

We study anisotropic stripe models of interacting electrons in the presence of magnetic fields in the quantum Hall regime with integer and fractional filling factors. The model consists of an infinite strip of finite width that contains…

Mesoscale and Nanoscale Physics · Physics 2014-08-06 Jelena Klinovaja , Daniel Loss

Graphene in the quantum Hall regime exhibits a multi-component structure due to the electronic spin and chirality degrees of freedom. While the applied field breaks the spin symmetry explicitly, we show that the fate of the chirality SU(2)…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 M. O. Goerbig , R. Moessner , B. Doucot

We study the spin exchange between two electrons localized in separate quantum dots in graphene. The electronic states in the conduction band are coupled indirectly by tunneling to a common continuum of delocalized states in the valence…

Mesoscale and Nanoscale Physics · Physics 2016-01-20 Matthias Braun , P. R. Struck , Guido Burkard

We report on our accurate evaluation of spin polarizations of the ground state and particle-hole gaps for partially-filled lowest Landau level, observed in recent experiments on graphene subjected to ultra-high magnetic fields. We find that…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Tapash Chakraborty , Pekka Pietilainen

Due to Klein tunneling in graphene only quasi-bound states are realized in graphene quantum dots by electrostatic gating. Particles in the quasi-bound states are trapped inside the dot for a finite time and they keep bouncing back and forth…

Mesoscale and Nanoscale Physics · Physics 2018-08-29 Abdelhadi Belouad , Youness Zahidi , Ahmed Jellal , Hocine Bahlouli

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

We show within a local self-consistent mean-field treatment that a random distribution of magnetic adatoms can open a robust gap in the electronic spectrum of graphene. The electronic gap results from the interplay between the nature of the…

Strongly Correlated Electrons · Physics 2011-10-11 T. G. Rappoport , M. Godoy , B. Uchoa , R. R dos Santos , A. H. Castro Neto

The fractal spectrum of magnetic minibands (Hofstadter butterfly), induced by the moir\'e super- lattice of graphene on an hexagonal crystal substrate, is known to exhibit gapped Dirac cones. We show that the gap can be closed by slightly…

Mesoscale and Nanoscale Physics · Physics 2014-05-15 M. Diez , J. P. Dahlhaus , M. Wimmer , C. W. J. Beenakker

Kane and Mele predicted that in presence of spin-orbit interaction graphene realizes the quantum spin Hall state. However, exceptionally weak intrinsic spin-orbit splitting in graphene ($\approx 10^{-5}$ eV) inhibits experimental…

Mesoscale and Nanoscale Physics · Physics 2013-06-18 Gabriel Autès , Oleg V. Yazyev

The effects of intrinsic spin-orbit and Coulomb interactions on low-energy properties of finite width graphene armchair ribbons are studied by means of a Dirac Hamiltonian. It is shown that metallic states subsist in the presence of…

Strongly Correlated Electrons · Physics 2012-02-01 Mahdi Zarea , Nancy Sandler