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We study the effect of band gap on the ground-state properties of Dirac electrons in a doped graphene within the random phase approximation at zero temperature. Band gap dependence of the exchange, correlation and ground-state energies and…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Alireza Qaiumzadeh , Reza Asgari

We have shown that the study of topological aspects of the underlying geometry in a ferromagnetic spin system gives rise to an intrinsic Berry phase. This real space Berry phase arises due to the spin rotations of conducting electrons which…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 B. Basu , P. Bandyopadhyay

The Berry phase and the group-velocity-based traversal time have been calculated for an asymmetric non-contacted or contacted graphene structure, and significant differences have been observed compared to semiconductor heterostructures.…

Mesoscale and Nanoscale Physics · Physics 2015-05-28 Daniela Dragoman

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…

We report the phase-space defined by the quantum Hall effect breakdown in polymer gated epitaxial graphene on SiC (SiC/G) as a function of temperature, current, carrier density, and magnetic fields up to 30T. At 2K breakdown currents…

We study the recently observed graphene fractional quantum Hall state at a filling factor $\nu_G=1/3$ using a four-component trial wave function and exact diagonalization calculations. Although it is adiabatically connected to a 1/3…

Mesoscale and Nanoscale Physics · Physics 2010-10-22 Z. Papic , M. O. Goerbig , N. Regnault

When smooth, zero-on-average, periodic magnetic and electric fields are applied to a carbon mono-layer (graphene), a gap between the valence and conduction band is introduced. Here this gapped state is studied analytically. It is found that…

Mesoscale and Nanoscale Physics · Physics 2013-02-25 I. Snyman

In a heterostructure of graphene and the ferromagnetic insulator EuO, the Eu atoms induce proximity exchange and inter-valley interactions in the graphene layer. Constrained by the lattice symmetries, and guided by ab initio calculations, a…

Materials Science · Physics 2017-04-11 Shanshan Su , Yafis Barlas , Roger K. Lake

Both topological crystalline insulators surfaces and graphene host multi-valley massless Dirac fermions which are not pinned to a high-symmetry point of the Brillouin zone. Strain couples to the low-energy electrons as a time-reversal…

Strongly Correlated Electrons · Physics 2016-05-18 Jörn W. F. Venderbos , Liang Fu

We study the quantum Hall effect in a monolayer graphene by using an approach based on thermodynamical properties. This can be done by considering a system of Dirac particles in an electromagnetic field and taking into account of the edges…

Mesoscale and Nanoscale Physics · Physics 2016-04-20 Ahmed Jellal

The paper addresses boundary electronic properties of graphene with a complex edge structure of the armchair/zigzag/armchair type. It is shown that the finite zigzag region supports edge bound states with discrete equidistant spectrum…

Mesoscale and Nanoscale Physics · Physics 2009-02-02 Grigory Tkachov

The electronic behavior in graphene under arbitrary uniaxial deformations, such as foldings or flexural fields is studied by including in the Dirac equation pseudoelectromagnetic fields. General foldings are thus studied by showing that…

Mesoscale and Nanoscale Physics · Physics 2023-03-23 Abdiel E. Champo , Gerardo G. Naumis

Inspired by experiments on magic angle twisted bilayer graphene, we present a lattice mean-field model for the quantum anomalous Hall effect in a moir\'e setting. Our hopping model thus provides a simple route to a moir\'e Chern insulator…

Mesoscale and Nanoscale Physics · Physics 2023-07-05 Ahmed Khalifa , Ganpathy Murthy , Ribhu K. Kaul

We discuss the novel electronic properties of graphene under an external periodic scalar or vector potential, and the analytical and numerical methods used to investigate them. When graphene is subjected to a one-dimensional periodic scalar…

Materials Science · Physics 2011-02-21 Cheol-Hwan Park , Liang Zheng Tan , Steven G. Louie

In this work we study theoretically the electronic properties of a sheet of graphene grown on a periodic heterostructure substrate. We write an effective Dirac equation, which includes a dependence of both the band gap and the Fermi…

Materials Science · Physics 2014-11-12 Jonas R. F. Lima , F. Moraes

Berry phase is one of the key elements to understand quantum-mechanical phenomena such as the Aharonov-Bohm effect and the unconventional Hall effect in graphene. The Berry phase in monolayer and bilayer graphene has been manifested by the…

Materials Science · Physics 2024-08-15 Hayoon Im , Sue Hyeon Hwang , Minhee Kang , Kyoo Kim , Haeyong Kang , Choongyu Hwang

Graphene properties can be manipulated by a periodic potential. Based on the tight-binding model, we study graphene under a one-dimensional (1D) modulated magnetic field which contains both a uniform and a staggered component. New chiral…

Strongly Correlated Electrons · Physics 2011-01-18 Lei Xu , Jin An , Chang-De Gong

We analyze a gap equation for the propagator of Dirac quasiparticles and conclude that in graphene in a magnetic field, the order parameters connected with the quantum Hall ferromagnetism dynamics and those connected with the magnetic…

Mesoscale and Nanoscale Physics · Physics 2008-11-26 E. V. Gorbar , V. P. Gusynin , V. A. Miransky

Recent experiments on rhombohedral pentalayer graphene flakes with a substrate induced moir\'e potential have identified both Chern insulators and fractional Quantum Hall states in the absence of an applied magnetic field. Surprisingly,…

Strongly Correlated Electrons · Physics 2024-11-15 Junkai Dong , Taige Wang , Tianle Wang , Tomohiro Soejima , Michael P. Zaletel , Ashvin Vishwanath , Daniel E. Parker

The intrinsic anomalous Hall effect in metallic ferromagnets is shown to be controlled by Berry phases accumulated by adiabatic motion of quasiparticles on the Fermi surface, and is purely a Fermi-liquid property, not a ``bulk'' Fermi sea…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 F. D. M. Haldane