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Graphene is a nonmagnetic semimetal and cannot be directly used as electronic or spintronic devices. We demonstrate that graphene quantum dots (GQDs) can exhibit strong edge magnetism and tunable energy gaps due to the presence of localized…

Materials Science · Physics 2017-11-01 Wei Hu , Yi Huang , Lin Lin , Erjun Kan , Xingxing Li , Chao Yang , Jinlong Yang

Quantum dots induced by a strong magnetic field applied to a single layer of graphene in the perpendicular direction are investigated. The dot is defined by a model potential which consists of a well of depth $\Delta V$ relative to a flat…

Mesoscale and Nanoscale Physics · Physics 2015-05-19 P. A. Maksym , M. Roy , M. F. Craciun , M. Yamamoto , S. Tarucha , H. Aoki

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

The co-presence of multiple Dirac bands in few-layer graphene leads to a rich phase diagram in the quantum Hall regime. Using transport measurements, we map the phase diagram of BN-encapsulated ABA-stacked trilayer graphene as a function…

Mesoscale and Nanoscale Physics · Physics 2016-08-24 Petr Stepanov , Yafis Barlas , Tim Espiritu , Shi Che , Kenji Watanabe , Takashi Taniguchi , Dmitry Smirnov , Chun Ning Lau

We probe quantum Hall effect in a tunable 1-D lateral superlattice (SL) in graphene created using electrostatic gates. Lack of equilibration is observed along edge states formed by electrostatic gates inside the superlattice. We create…

Mesoscale and Nanoscale Physics · Physics 2016-05-03 Sudipta Dubey , Mandar M. Deshmukh

The effect of a varying pseudo-magnetic field, which falls as $1/x^2$, on a two dimensional electron gas in graphene is investigated. By considering the second order Dirac equation, we show that its correct general solution is that which…

Mesoscale and Nanoscale Physics · Physics 2015-01-29 L. G. da Silva Leite , D. Cogollo , C. Filgueiras , Edilberto O. Silva

Graphene on two dimensional (2D) noncommutative (NC) plane in the presence of a constant background magnetic field has been studied. To handel the gauge-invariance issue we start our analysis by a effective massles NC Dirac field theory…

High Energy Physics - Theory · Physics 2020-10-28 Aslam Halder

Dynamic wavelength tunability has long been the holy grail of photodetector technology. Because of its atomic thickness and unique properties, graphene opens up new paradigms to realize this concept, but so far this has been elusive…

Mesoscale and Nanoscale Physics · Physics 2017-03-08 François Léonard , Catalin D. Spataru , Michael Goldflam , David W. Peters , Thomas E. Beechem

The present article discusses magnetic confinement of the Dirac excitations in graphene in presence of inhomogeneous magnetic fields. In the first case a magnetic field directed along the z axis whose magnitude is proportional to $1/r$ is…

Mesoscale and Nanoscale Physics · Physics 2015-05-30 Pratim Roy , Tarun Kanti Ghosh , Kaushik Bhattacharya

We theoretically analyze the energy spectrum of a quantum ring in AA-stacked bilayer graphene with radius $R$ for a zero width subjected to a perpendicular magnetic field $B$. An analytical approach, using the Dirac equation, is implemented…

Mesoscale and Nanoscale Physics · Physics 2016-10-31 Youness Zahidi , Abdelhadi Belouad , Ahmed Jellal

It is well-known that the tight-binding Hamiltonian of graphene describes the low-energy excitations that appear to be massless chiral Dirac fermions. Thus, in the continuum limit one can analyze the crystal properties using the formalism…

Materials Science · Physics 2012-11-03 P. Kosinski , P. Maslanka , J. Slawinska , I. Zasada

In this paper, we show, by using the approach of effective mass, that the model of a two-dimensional Dirac oscillator can be used to describe the thermal properties of graphene under an uniform magnetic field. All thermal quantities of…

Mesoscale and Nanoscale Physics · Physics 2015-09-30 Abdelmalek Boumali

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

Under strong laser fields, electrons in solids radiate high-harmonic fields by travelling through quantum pathways in Bloch bands in the sub-laser-cycle timescales. Understanding these pathways in the momentum space through the…

In this paper we obtain exact solutions of a 2D relativistic Dirac oscillator in the presence of a constant magnetic field. We compute the energy spectrum and discuss its dependence on the spin and magnetic field strength.

Mesoscale and Nanoscale Physics · Physics 2015-06-24 V. M. Villalba , A. Rincon Maggiolo

The electronic states of an electrostatically confined cylindrical graphene quantum dot and the electric transport through this device are studied theoretically within the continuum Dirac-equation approximation and compared with numerical…

Mesoscale and Nanoscale Physics · Physics 2011-08-12 G. Pal , W. Apel , L. Schweitzer

We investigate the addition spectrum of a graphene quantum dot in the vicinity of the electron-hole crossover as a function of perpendicular magnetic field. Coulomb blockade resonances of the 50 nm wide dot are visible at all gate voltages…

Materials Science · Physics 2009-08-04 J. Guettinger , C. Stampfer , F. Libisch , T. Frey , J. Burgdoerfer , T. Ihn , K. Ensslin

We report an atomically-precise integration of individual nitrogen (N) dopant as an in-plane artificial nucleus in a graphene device by atomic implantation to probe its gate-tunable quantum states and correlation effects. The N dopant…

We investigate the conductance of an undoped graphene sheet with two metallic contacts and an electrostatically gated island (quantum dot) between the contacts. Our analysis is based on the Matrix Green Function formalism, which was…

Mesoscale and Nanoscale Physics · Physics 2011-10-05 Martin Schneider , Piet W. Brouwer

Quantum states in graphene are four-fold degenerate: two fold in spins, and two fold in valleys.Both degrees of freedom can be utilized for qubit preparations. In our bilayer graphene quantumdots, we demonstrate that the valley g-factorgv,…