Klein tunneling in single and multiple barriers in graphene

Pereira, J. Milton; Peeters, F. M.; Chaves, Andrey; Farias, G. A.

doi:10.1088/0268-1242/25/3/033002

Cited by 110 publications

(91 citation statements)

References 30 publications

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“…Such processes are allowed, since both states have the same structure in pseudospin space; they are proportional to (−1,1) T . Since the Fourier components U k−k decay as a function of |k − k | , being the spatial scale of the potential, this intervalley scattering can be strongly suppressed by considering a smooth barrier (20), with a sufficiently large value of . In Fig.…”

Section: Beyond the Dirac Regimementioning

confidence: 99%

Modeling Klein tunneling and caustics of electron waves in graphene

et al. 2015

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Please be advised that this information was generated on 2018-05-09 and may be subject to change. PHYSICAL REVIEW B 91, 045420 (2015) Modeling Klein tunneling and caustics of electron waves in graphene We employ the tight-binding propagation method to study Klein tunneling and quantum interference in large graphene systems. With this efficient numerical scheme, we model the propagation of a wave packet through a potential barrier and determine the tunneling probability for different incidence angles. We consider both sharp and smooth potential barriers in n-p-n and n-n junctions and find good agreement with analytical and semiclassical predictions. When we go outside the Dirac regime, we observe that sharp n-p junctions no longer show Klein tunneling because of intervalley scattering. However, this effect can be suppressed by considering a smooth potential. Klein tunneling holds for potentials changing on the scale much larger than the interatomic distance. When the energies of both the electrons and holes are above the Van Hove singularity, we observe total reflection for both sharp and smooth potential barriers. Furthermore, we consider caustic formation by a two-dimensional Gaussian potential. For sufficiently broad potentials we find a good agreement between the simulated wave density and the classical electron trajectories.

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Section: Beyond the Dirac Regimementioning

confidence: 99%

Modeling Klein tunneling and caustics of electron waves in graphene

et al. 2015

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“…chiral nature of graphene. The theoretical discussion of chiral tunneling so far focuses mainly on spin-independent tunneling through pn and pnp junctions, 21,22,[24][25][26][27][28][29][30] while SOC effects are less discussed. 18,[31][32][33] In addition, the relevant theoretical understanding so far is based on Dirac theory, which is valid only for the Fermi level close to the charge neutrality point and allows one only to consider certain relatively simple systems.…”

Section: Introductionmentioning

confidence: 99%

Spin-dependent Klein tunneling in graphene: Role of Rashba spin-orbit coupling

2012

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Within an effective Dirac theory the low-energy dispersions of monolayer graphene in the presence of Rashba spin-orbit coupling and spin-degenerate bilayer graphene are described by formally identical expressions. We explore implications of this correspondence for transport by choosing chiral tunneling through pn and pnp junctions as a concrete example. A real-space Green's function formalism based on a tight-binding model is adopted to perform the ballistic transport calculations, which cover and confirm previous theoretical results based on the Dirac theory. Chiral tunneling in monolayer graphene in the presence of Rashba coupling is shown to indeed behave like in bilayer graphene. Combined effects of a forbidden normal transmission and spin separation are observed within the single-band n ↔ p transmission regime. The former comes from real-spin conservation, in analogy with pseudospin conservation in bilayer graphene, while the latter arises from the intrinsic spin-Hall mechanism of the Rashba coupling.

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“…However, the chiral nature of the charge carriers in graphene, together with their gapless spectrum, gives rise to the phenomenon of Klein tunneling, i.e. the perfect transmission of normally-incident electrons through a potential barrier [3,4]. This unusual phenomenon causes difficulties for the creation of logic devices, due to the fact that, for wide graphene samples it may not be possible to obtain an "off" state, in which there is no flow of current.…”

Section: Introductionmentioning

confidence: 99%

Interferometry of Klein tunnelling electrons in graphene quantum rings

Sousa

Chaves

Pereira

et al. 2017

Journal of Applied Physics

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We theoretically study a current switch that exploits the phase acquired by a charge carrier as it tunnels through a potential barrier in graphene. The system acts as an interferometer based on an armchair graphene quantum ring, where the phase difference between interfering electronic wave functions for each path can be controlled by tuning either the height or the width of a potential barrier in the ring arms. By varying the parameters of the potential barriers the interference can become completely destructive. We demonstrate how this interference effect can be used for developing a simple graphene-based logic gate with high on/off ratio.

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Klein tunneling in single and multiple barriers in graphene

Cited by 110 publications

References 30 publications

Modeling Klein tunneling and caustics of electron waves in graphene

Modeling Klein tunneling and caustics of electron waves in graphene

Spin-dependent Klein tunneling in graphene: Role of Rashba spin-orbit coupling

Interferometry of Klein tunnelling electrons in graphene quantum rings

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