Aharonov–Bohm interferences in polycrystalline graphene

Nguyễn, Việt Hùng; Charlier, Jean‐Christophe

doi:10.1039/c9na00542k

Cited by 7 publications

(6 citation statements)

References 76 publications

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“…The negative magnitude of the band gap can be attributed to the overlap of the bottom of the conduction band (CB) with the top of the valence band (VB), a phenomenon observed in the case of metals or gapless semiconductors or semimetals [81,82]. This kind of behavior is consistent with the recently observed results on CNTs [65], wherein this changeover was attributed to the Aharonov-Bohm effect [83]. Careful observation of figure 2 suggests that the transition magnetic field for graphene and h-boron nitride nanoribbons is 0.45 T, whereas for silicene and germanene it is 0.8 T and 0.2 T respectively.…”

Section: Resultssupporting

confidence: 87%

Band gap determination of graphene, h-boron nitride, phosphorene, silicene, stanene, and germanene nanoribbons

Pandya

Sangani

Jha

2020

J. Phys. D: Appl. Phys.

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The energy band gap of graphene, h-boron nitride, stanene, silicene, germanene, and phosphorene nanoribbons is investigated theoretically with two approaches. In the first approach, a set of equations to calculate the energy band gap of nanoribbons is deduced using the expression of Fermi velocity. The size dependency of the energy band gap so obtained confirms previous expressions. The second approach, however, determines resistivity by directly connecting quantity to the energy band gap using an electron-acoustical phonon scattering mechanism. For the calculation of the energy band gap and resistivity, the armchair configuration of nanoribbons is considered. It is observed that the transverse magnetic field influences the energy band gap and resistivity. The magnitude of the band gap is negative up to a certain value of the field and turns positive at a sufficiently higher field. The negative band gap can be interpreted as metallic behavior of the materials. The results of the work are useful in the determination of the energy band gap of nanoribbons for their nanoelectronic and optoelectronic applications as well as tuning the band gap using the applied magnetic field.

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Section: Resultssupporting

confidence: 87%

Band gap determination of graphene, h-boron nitride, phosphorene, silicene, stanene, and germanene nanoribbons

Pandya

Sangani

Jha

2020

J. Phys. D: Appl. Phys.

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“…A novel fascinating magnetotransport feature has been recently predicted in polycrystalline graphene [46]. In particular, the extended states strongly localized along the grain boundaries can be exploited to create tunneling paths connecting quantum Hall edge channels in CVD graphene samples.…”

Section: Electronic Transport In Polycrystalline Graphenementioning

confidence: 99%

“…This necessarily leads to discrepancies between experimental measurements in PG and theoretical predictions of transport properties of "ideal" GBs. Our researches focus on the systematic study of the electronic transport through realistic graphene grain boundaries [43,44] and on the exploration of novel phenomena such as valley-dependent transport, electron optics effects, Aharonov-Bohm interferences and spin-diffusion lengths in polycrystalline graphene [45][46][47].…”

Section: Electronic Transport In Polycrystalline Graphenementioning

confidence: 99%

“…This empirical potential model has been shown to accurately describe the structural properties of defective graphene [49]. The electronic properties of defective graphene systems under study were calculated using either the first-principles approach [44] or the π-orbital TB technique [43,45,46]. First-principles calculations were performed using DFT within the OPENMX code [50][51][52], a software package based on norm-conserving pseudo-potentials and pseudo-atomic localized basis functions.…”

Section: Electronic Transport In Polycrystalline Graphenementioning

confidence: 99%

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Computational Atomistic Modeling in Carbon Flatland and Other 2D Nanomaterials

et al. 2020

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As in many countries, the rise of nanosciences in Belgium has been triggered in the eighties in the one hand, by the development of scanning tunneling and atomic force microscopes offering an unprecedented possibility to visualize and manipulate the atoms, and in the other hand, by the synthesis of nano-objects in particular carbon nanostructures such as fullerene and nanotubes. Concomitantly, the increasing calculating power and the emergence of computing facilities together with the development of DFT-based ab initio softwares have brought to nanosciences field powerful simulation tools to analyse and predict properties of nano-objects. Starting with 0D and 1D nanostructures, the floor is now occupied by the 2D materials with graphene being the bow of this 2D ship. In this review article, some specific examples of 2D systems has been chosen to illustrate how not only density functional theory (DFT) but also tight-binding (TB) techniques can be daily used to investigate theoretically the electronic, phononic, magnetic, and transport properties of these atomically thin layered materials.

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“…For practical applications, the large-area 2D materials synthesized by chemical vapor deposition technique are always found to be polycrystalline in nature [51][52][53][54][55][56][57][58][59][60][61] which consists of two domains with different crystallographic orientations and the GBs stitching them together. Similar to their pristine forms, the polycrystalline also exhibits many peculiar electronic features and transport characteristics, such as thermal transport properties [62][63][64][65][66], magnetic properties [67][68][69][70][71][72], spin filtering [73][74][75], the quantum Hall effect [76][77][78][79] and so on. These features suggest that they have significant applications in the charge-and spinbased electronics.…”

Section: Introductionmentioning

confidence: 99%

Valleytronics in two-dimensional materials with line defect

2022

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The concept of valley originates from two degenerate but nonequivalent energy bands at the local minimum in the conduction band or local maximum in the valence band. Manipulating the valley states for information storage and processing develops a brand-new electronics --- valleytronics. Broken inversion symmetry is a necessary condition to produce pure valley currents. The polycrystalline two-dimensional (2D) materials (graphene, silicene, monolayer group-VI transition metal dichalcogenides, etc.) with pristine grains stitched together by disordered grain boundaries (GBs) are the natural inversion-symmetry-broken systems and the candidates in the field of valleytronics. Different from their pristine forms, the Dirac valleys on both sides of GBs are mismatched in the momentum space and induce peculiar valley transport properties across the GBs. In this review, we systematically demonstrate the fundamental properties of valley degree of freedom across mostly studied and experimentally feasible polycrystalline structure --- the line defect, and the manipulation strategies with electrical, magnetic and mechanical methods to realize the valley polarization. We also introduce an effective numerical method, the non-equilibrium Green's function technique, to tackle the valley transport issues in the line defect systems. The present challenges and the perspective on the further investigations of the line defect in valleytronics are also summarized.

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Aharonov–Bohm interferences in polycrystalline graphene

Cited by 7 publications

References 76 publications

Band gap determination of graphene, h-boron nitride, phosphorene, silicene, stanene, and germanene nanoribbons

Band gap determination of graphene, h-boron nitride, phosphorene, silicene, stanene, and germanene nanoribbons

Computational Atomistic Modeling in Carbon Flatland and Other 2D Nanomaterials

Valleytronics in two-dimensional materials with line defect

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