Electronic structure of a graphene superlattice with a modulated Fermi velocity

Lima, Jonas R.F.

doi:10.1016/j.physleta.2015.02.034

Cited by 22 publications

(8 citation statements)

References 33 publications

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“…In the contact points, where the band structures are intersected, the gradient of dispersion relation (39) must be equal zero [24]. This implies that the contact point (k xc , k yc , ε c ) has to verify f (k xc , k yc , ε c ) = 0, ∇f (k xc , k yc , ε c ) = 0. where the involved parameter is…”

Section: Appendixmentioning

confidence: 99%

Band structures of symmetrical graphene superlattice with cells of three regions

2018

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We study the electronic band structures of massless Dirac fermions in symmetrical graphene superlattice with cells of three regions. Using the transfer matrix method, we explicitly determine the dispersion relation in terms of different physical parameters. We numerically analyze such relation and show that there exist three zones: bound, unbound and forbidden states. In the central zone of the band structures, we determine and enumerate the vertical Dirac points, opening gaps and additional Dirac points. Finally, we inspect the potential effect on minibands, the anisotropy of group velocity and the energy bands contours near Dirac points. We also discuss the evolution of gap edges and cutoff region near the vertical Dirac points.

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Section: Appendixmentioning

confidence: 99%

Band structures of symmetrical graphene superlattice with cells of three regions

2018

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“…At the Dirac point (k Dx , k Dy , ε D ), the band structures are intersected. Then the gradient of dispersion relation must be equal zero [17], namely…”

Section: Model and Methodsmentioning

confidence: 99%

Zitterbewegung Effect in Graphene with Spacially Modulated Potential

Kamal,

Jellal

2020

Preprint

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The Zitterbewegung (ZB) effect is investigated in graphene with spacially modulated potential near the original Dirac point (ODP) and extra Dirac points (EDPs). Our calculations show that to get the large ZB oscillations, the wave packet center must be at the angle θ 0 = 0 for EDPs located at zero-energy, or θ 0 = π/2 for both ODP and EDPs at finite energy ε = mπ (m integer). By varying the parameters (q 2 , V) of the periodic potential and the initial momentum (κ 0 , θ 0 ) of Gaussian wave packet, it is found that the frequency of the ZB oscillations is in the range [10 7 Hz, 10 13 Hz] depending on what type of EDP is generated and the amplitude reaches hundreds of angstroms but their attenuation becomes very slow. More analysis of the frequency shows the possibilities in experimentally realizing the ZB effect in our system.

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“…In the last years, various studies have revealed that the electronic and transport properties of graphene can be controlled by a Fermi velocity engineering [43,44]. For instance, it was obtained that a Fermi velocity modulation in graphene can control the energy gap [45] and also induce an indirect energy gap in monolayer [46] and bilayer [47] graphene.…”

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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Electronic structure of a graphene superlattice with a modulated Fermi velocity

Cited by 22 publications

References 33 publications

Band structures of symmetrical graphene superlattice with cells of three regions

Band structures of symmetrical graphene superlattice with cells of three regions

Zitterbewegung Effect in Graphene with Spacially Modulated Potential

Perfect valley filter controlled by Fermi velocity modulation in graphene

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