Angle-dependent bandgap engineering in gated graphene superlattices

García-Cervantes, Heraclio; Gaggero‐Sager, L. M.; Sotolongo‐Costa, Oscar; Naumis, Gerardo G.; Rodrı́guez-Vargas, I.

doi:10.1063/1.4944495

Cited by 13 publications

(10 citation statements)

References 66 publications

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“…R-Square is 0.99774 for the fit, which suggests that the fitting is perfect. It is worth to stress that Lorentz like relationship between the incident angle and the bandgaps is unique to this 3D Weyl semimetal based superlattice, since a parabolic dependence in a small angle and an exponential dependence at a big angle are found for the case of 2D relativistic fermion 55 . Besides, the first artificial bandgaps rang from 0.42 to 17 which have a strong appeal to the engineer community due to its multiply possible technological implications.…”

Section: Resultsmentioning

confidence: 81%

Chiral tunneling in gated inversion symmetric Weyl semimetal

Bai

Yang

Chang

2016

Sci Rep

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Based on the chirality-resolved transfer-matrix method, we evaluate the chiral transport tunneling through Weyl semimetal multi-barrier structures created by periodic gates. It is shown that, in sharp contrast to the cases of three dimensional normal semimetals, the tunneling coefficient as a function of incident angle shows a strong anisotropic behavior. Importantly, the tunneling coefficients display an interesting periodic oscillation as a function of the crystallographic angle of the structures. With the increasement of the barriers, the tunneling current shows a Fabry-Perot type interferences. For superlattice structures, the fancy miniband effect has been revealed. Our results show that the angular dependence of the first bandgap can be reduced into a Lorentz formula. The disorder suppresses the oscillation of the tunneling conductance, but would not affect its average amplitude. This is in sharp contrast to that in multi-barrier conventional semiconductor structures. Moreover, numerical results for the dependence of the angularly averaged conductance on the incident energy and the structure parameters are presented and contrasted with those in two dimensional relativistic materials. Our work suggests that the gated Weyl semimetal opens a possible new route to access to new type nanoelectronic device.

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Section: Resultsmentioning

confidence: 81%

Chiral tunneling in gated inversion symmetric Weyl semimetal

Bai

Yang

Chang

2016

Sci Rep

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“…In this appendix we derive Eqs. (13), (14), (15), and (16). We start by studying each case out of the four possible for Eq.…”

Section: Appendix Amentioning

confidence: 99%

Landauer-Büttiker conductivity for spatially-dependent uniaxial strained armchair-terminated graphene nanoribbons

Espinosa-Champo

Roman‐Taboada

Naumis

2018

Physica E: Low-dimensional Systems and Nanostructures

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The Landauer-Büttiker conductivity of arbitrary uniaxial spatially dependent strain in an armchair graphene nanoribbon is studied. Due to the uniaxial character of the strain, the corresponding transfer matrix can be reduced to a product of 2 × 2 matrices. Then the conductivity and the Fano factor can be calculated from this product. As an example of the technique, sinusoidal space dependent strain fields are studied using two different strain wavelengths. For the bigger wavelength the conductivity is reduced when compared with the unstrained case, although both conductivities are almost the same in shape. Whereas, for the smaller wavelength case, the conductivity is strongly modified. In spite of this, for energies close to the Dirac point energy, the conductivity and the Fano factor are quite similar to their unstrained counterpart for the two strain wavelengths here studied.

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“…This effect, known as Klein tunneling, [10][11][12] contrasts with the case of nonrelativistic electron where the probability that a particle is transmitted decays exponentially with the height of the barrier. Klein tunneling occurs not only through a single potential barrier but also on many barriers, [13][14][15] whether or not they have periodical order. When the electrons impinge with an angle different from zero, the Klein tunneling disappears, and now the system presents a set of resonances with transmittance equal to one.…”

Section: Introductionmentioning

confidence: 99%