Velocity-controlled guiding of electron in graphene: Analogy of optical waveguides

Yuan, Jian-Hui; Cheng, Ze; Zeng, Qi-Jun; Zhang, Junpei; Zhang, Jianjun

doi:10.1063/1.3660748

Cited by 39 publications

(26 citation statements)

References 65 publications

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“…There are several works that have addressed the modelling of a spatially dependent Fermi velocity with a different phenomenological model, which amounts to the direct replacement of v F by a scalar function v(x) in the Hamiltonian [98,99,100,101,102]. This model is equivalent to considering just the isotropic coupling to the strain H 4 with a scalar function v(x) = v F u kk .…”

Section: Quantum Field Theory In Curved Spacesmentioning

confidence: 99%

Novel effects of strains in graphene and other two dimensional materials

Amorim¹,

Cortijo²,

Juan³

et al. 2016

Physics Reports

385

401

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√s NN = 5.02 TeV using the ALICE detector at the LHC. The measurement covers the p T interval 0.5 < p T < 12 GeV/c and the rapidity range −1.065 < y cms < 0.135 in the centre-of-mass reference frame. The contribution of electrons from background sources was subtracted using an invariant mass approach. The nuclear modification factor R pPb was calculated by comparing the p T -differential invariant cross section in p-Pb collisions to a pp reference at the same centre-of-mass energy, which was obtained by interpolating measurements at √ s = 2.76 TeV and √ s = 7 TeV. The R pPb is consistent with unity within uncertainties of about 25%, which become larger for p T below 1 GeV/c. The measurement shows that heavy-flavour production is consistent with binary scaling, so that a suppression in the high-p T yield in Pb-Pb collisions has to be attributed to effects induced by the hot medium produced in the final state. The data in p-Pb collisions are described by recent model calculations that include cold nuclear matter effects. IntroductionThe Quark-Gluon Plasma (QGP) [1,2], a colour-deconfined state of strongly-interacting matter, is predicted to exist at high temperature according to lattice Quantum Chromodynamics (QCD) calculations [3]. These conditions can be reached in ultra-relativistic heavy-ion collisions [4][5][6][7][8][9][10]. Charm and beauty (heavy-flavour) quarks are mostly produced in initial hard scattering processes on a very short time scale, shorter than the formation time of the QGP medium [11], and thus experience the full temporal and spatial evolution of the collision. While interacting with the QGP medium, heavy quarks lose energy via elastic and radiative processes [12][13][14]. Heavy-flavour hadrons are therefore well-suited probes to study the properties of the QGP. The effect of energy loss on heavy-flavour production can be characterised via the nuclear modification factor (R AA ) of heavy-flavour hadrons. The R AA is defined as the ratio of the heavy-flavour hadron yield in nucleusnucleus (A-A) collisions to that in proton-proton (pp) collisions scaled by the average number of binary nucleon-nucleon collisions. The R AA is studied differentially as a function of transverse momentum (p T ), rapidity ( y) and collision centrality. It was measured at the Relativistic Heavy Ion Collider (RHIC) [15][16][17][18] and at the Large Hadron Collider (LHC) [19][20][21][22]. At RHIC, in central The interpretation of the measurements in A-A collisions requires the study of heavy-flavour production in p-A collisions, which provides access to cold nuclear matter (CNM) effects. These effects are not related to the formation of a colour-deconfined medium, but are present in case of colliding nuclei (or protonnucleus). An important CNM effect in the initial state is partondensity shadowing or saturation, which can be described using modified parton distribution functions (PDF) in the nucleus [23] or using the Color Glass Condensate (CGC) effective theory [24]. Further CNM effects include energy loss [25] in...

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Section: Quantum Field Theory In Curved Spacesmentioning

confidence: 99%

Novel effects of strains in graphene and other two dimensional materials

Amorim¹,

Cortijo²,

Juan³

et al. 2016

Physics Reports

385

401

View full text Add to dashboard Cite

show abstract

“…The graphene is deposited on a heterostructured substrate composed by two different materials, which can open different energy gaps in different regions of the graphene sheet that will be denoted by ∆ 1 = 0 and ∆ 2 = ∆. The modulation of the Fermi velocity can be obtained in graphene by placing metallic planes close to the graphene sheet, which will turn electron-electron interactions weaker and, consequently, modify the Fermi velocity [32,33]. The Fermi velocity in each region will be denoted by v 1 and v 2 .…”

Section: Modelmentioning

confidence: 99%

Electronic structure of a graphene superlattice with a modulated Fermi velocity

Lima

2015

Physics Letters A

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The electronic structure of a graphene superlattice composed by two periodic regions with different Fermi velocity, energy gap and electrostatic potential is investigated by using an effective Dirac-like Hamiltonian. It must be expected that the change of the Fermi velocity in one region of the graphene superlattice is equivalent to changing the width of this region keeping the Fermi velocity unchanged, provided that the time taken to charge carriers cross the region is the same. However, it is shown here that these two systems are not equivalent. We found extra Dirac points induced by the periodic potential and their location in the k space. It is shown that the Fermi velocity modulation breaks the symmetry between the electron and hole minibands and that it is possible to control the behavior of the extra Dirac points. The results obtained here can be used in the fabrication of graphene-based electronic devices.

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“…The Fermi velocity in graphene can be engeneered, for instance, by the substrate [52], by doping [53] and by strain [54,55]. As the Fermi velocity in graphene depends on the electron concentration [3,56,57], it is possible to induce a positiondependent Fermi velocity placing metallic planes close to the graphene layer, since the presence of the planes will change the electron concentration in different regions [48,49]. Fermi velocities as high as 3 × 10 6 m/s were already obtained in graphene by electron's concentration modifications [56].…”

Section: Introductionmentioning

confidence: 99%

Perfect valley filter controlled by Fermi velocity modulation in graphene

Lins

Lima

2020

Carbon

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In this work we investigate the effects of a Fermi velocity modulation in a valley filter in graphene created by a combination of a magnetic and electric barrier. With the effective Dirac equation of the system, we use the transfer matrix formalism to obtain the transmittance. We verify that the valley transport in graphene is very sensitive to a Fermi velocity modulation, which is able to choose which valley will be filtered with perfect filtering. Also, it is possible to use a Fermi velocity modulation to filter both valleys or to make the valley filter transparent. It reveals that the Fermi velocity is a powerful tool that can be used to tune a graphene valley filter, since it has a total control in its transport properties. *

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Velocity-controlled guiding of electron in graphene: Analogy of optical waveguides

Cited by 39 publications

References 65 publications

Novel effects of strains in graphene and other two dimensional materials

Novel effects of strains in graphene and other two dimensional materials

Electronic structure of a graphene superlattice with a modulated Fermi velocity

Perfect valley filter controlled by Fermi velocity modulation in graphene

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