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Broadening of the Landau levels in graphene and the associated quantum Hall plateau-to-plateau transition are investigated numerically. For correlated bond disorder, the graphene-specific n=0 Landau level of the Dirac fermions becomes…

Mesoscale and Nanoscale Physics · Physics 2010-03-03 Tohru Kawarabayashi , Yasuhiro Hatsugai , Hideo Aoki

The lifting of the degeneracy of the states from the graphene $n$=0 Landau level (LL) is investigated through a non-interacting tight-binding model with random hoppings. A disorder-driven splitting of two bands and of two critical energies…

Mesoscale and Nanoscale Physics · Physics 2009-10-01 Ana L. C. Pereira

The zero-energy Landau level of bilayer graphene is shown to be anomalously sharp (delta-function like) against bond disorder as long as the disorder is correlated over a few lattice constants.The robustness of the zero-mode anomaly can be…

Mesoscale and Nanoscale Physics · Physics 2015-06-03 Tohru Kawarabayashi , Yasuhiro Hatsugai , Hideo Aoki

The stability of the zero-energy Landau levels in bilayer graphene against the chiral symmetric disorder is examined in the presence of the trigonal warping. Based on the tight-binding lattice model with a bond disorder correlated over…

Mesoscale and Nanoscale Physics · Physics 2015-06-11 Tohru Kawarabayashi , Yasuhiro Hatsugai , Hideo Aoki

Density of states (DOS) of graphene under a high uniform magnetic field and white-noise random potential is numerically calculated. The disorder broadened zero-energy Landau band has a Gaussian shape whose width is proportional to the…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 W. Zhu , Q. W. Shi , X. R. Wang , J. Chen , J. G. Hou

We report capacitors in which a finite electronic compressibility of graphene dominates the electrostatics, resulting in pronounced changes in capacitance as a function of magnetic field and carrier concentration. The capacitance…

Mesoscale and Nanoscale Physics · Physics 2010-09-22 L. A. Ponomarenko , R. Yang , R. V. Gorbachev , P. Blake , M. I. Katsnelson , K. S. Novoselov , A. K. Geim

In the anomalous quantum Hall effect (QHE), a hallmark of graphene, nature of the edge states in magnetic fields poses an important question, since the edge and bulk should be intimately related in QHE. Here we have theoretically studied…

Mesoscale and Nanoscale Physics · Physics 2009-05-01 Mitsuhiro Arikawa , Yasuhiro Hatsugai , Hideo Aoki

We investigate the effects of vacancies, disorder and sublattice polarization on the electronic properties of a monolayer graphene in the quantum Hall regime. Energy spectra as a function of magnetic field and the localization properties of…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 Ana L. C. Pereira , Peter A. Schulz

The lowest Landau level of graphene is studied numerically by considering a tight-binding Hamiltonian with disorder. The Hall conductance $\sigma_\mathrm{xy}$ and the longitudinal conductance $\sigma_\mathrm{xx}$ are computed. We…

Mesoscale and Nanoscale Physics · Physics 2008-07-16 Xun Jia , Pallab Goswami , Sudip Chakravarty

Recent successes in manufacturing of atomically thin graphite samples (graphene) have stimulated intense experimental and theoretical activity. The key feature of graphene is the massless Dirac type of low-energy electron excitations. This…

Mesoscale and Nanoscale Physics · Physics 2008-05-23 P. M. Ostrovsky , I. V. Gornyi , A. D. Mirlin

The electromagnetic response of bilayer graphene in a magnetic field is studied in comparison with that of monolayer graphene. Both types of graphene turn out to be qualitatively quite similar in dielectric and screening characteristics,…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 T. Misumi , K. Shizuya

While usual edge states in the quantum Hall effect(QHE) reside between adjacent Landau levels, QHE in graphene has a peculiar edge mode at E=0 that reside right within the n=0 Landau level as protected by the chiral symmetry. We have…

Mesoscale and Nanoscale Physics · Physics 2008-11-04 Mitsuhiro Arikawa , Yasuhiro Hatsugai , Hideo Aoki

Effects of disorder and valley polarization in graphene are investigated in the quantum Hall regime. We find anomalous localization properties for the lowest Landau level (LL), where disorder can induce wavefunction delocalization (instead…

Mesoscale and Nanoscale Physics · Physics 2008-02-21 Ana L. C. Pereira , P. A. Schulz

The electronic properties of non-interacting particles moving on a two-dimensional bricklayer lattice are investigated numerically. In particular, the influence of disorder in form of a spatially varying random magnetic flux is studied. In…

Disordered Systems and Neural Networks · Physics 2009-12-22 L. Schweitzer

Superlattices (SLs) in monolayer and bilayer graphene, formed by spatially periodic potential variations, lead to a modified bandstructure with extra finite-energy and zero-energy Dirac fermions with tunable anisotropic velocities. We…

Mesoscale and Nanoscale Physics · Physics 2012-05-14 Si Wu , Matthew Killi , Arun Paramekanti

We investigate, analytically and numerically, the effects of disorder on the density of states and on the localization properties of the relativistic two dimensional fermions in the lowest Landau level. Employing a supersymmetric technique,…

Mesoscale and Nanoscale Physics · Physics 2007-11-08 Pallab Goswami , Xun Jia , Sudip Chakravarty

The electronic Raman scattering of bulk graphite at zero magnetic field reveals a structureless signal characteristic of a metal. For T<~100 K and B > 2 T, several peaks at energies scaling linearly with magnetic field were observed and…

Mesoscale and Nanoscale Physics · Physics 2008-07-10 A. F. Garcia-Flores , H. Terashita , E. Granado , Y. Kopelevich

A monolayer graphene exists in an environment where a uniform magnetic field interacts a spatially modulated magnetic field. The spatially modulated magnetic field could affect Landau levels due to a uniform magnetic field. The modulation…

Mesoscale and Nanoscale Physics · Physics 2007-08-02 J. H. Ho , Y. H. Lai , Y. H. Chiu , M. F. Lin

We study the density of states and localization properties of the lowest Landau levels of graphene at high magnetic fields. We focus on the effects caused by correlated long-range hopping disorder, which, in exfoliated graphene, is induced…

Mesoscale and Nanoscale Physics · Physics 2011-10-06 A. L. C. Pereira , C. H. Lewenkopf , E. R. Mucciolo

In the absence of disorder, the degeneracy of a Landau level (LL) is $N=BA/\phi_0$, where $B$ is the magnetic field, $A$ is the area of the sample and $\phi_0=h/e$ is the magnetic flux quantum. With disorder, localized states appear at the…

Disordered Systems and Neural Networks · Physics 2015-05-13 Chenggang Zhou , Mona Berciu
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