One-dimensional quantum channel in a graphene line defect

Abstract

Using a tight-binding model, we study a line defect in graphene where a bulk energy gap is opened by sublattice symmetry breaking. It is found that sublattice symmetry breaking may induce many configurations that correspond to different band spectra. In particular, a gapless state is observed for a configuration which hold a mirror symmetry with respect to the line defect. We find that this gapless state originates from the line defect and is independent of the width of the graphene ribbon, the location of the line defect, and the potentials in the edges of the ribbon. In particular, the gapless state can be controlled by the gate voltage embedded below the line defect. Finally, this result is supported with conductance calculations. This study shows how a quantum channel could be constructed using a line defect, and how the quantum channel can be controlled by tuning the gate voltage embedded below the line defect.Comment: 8 pages, 10 figure

Topological phases in two-dimensional materials: a review

“…The superlattices with adjacent AB and BA stacking orders, with boundaries that may support ZLMs, can also be realized in graphene on top of h-BN substrates as a result of lattice mismatch [315]. In addition to the line defect exhibited when the stacking order of bilayer graphene changes, 1D ZLMs can also appear along the line defect of monolayer graphene if a suitable staggered sublattice potential is present [316].…”

Grain boundaries with octagonal defects in graphene nanoribbons and nanotubes

“…2 Electronic and magnetic properties of ribbons with octagon-pentagon line defects are now being intensively investigated. [19][20][21][22] In this work we study the appearance of localized states in graphene-based systems with octagonal defects. We investigate octagonal defect lines appearing both in graphene ribbons and in carbon nanotubes, which can be considered as rolled-up ribbons.…”

Electron interaction, charging, and screening at grain boundaries in graphene

“…The first one, (2,0), consists of domains with the aligned crystallographic orientations θ L = θ R = θ = 0 • (d ≈ 0.5 nm) and separated by a zigzag-oriented interface of one octagon and two side-sharing pentagons. [16][17][18][19]23 The repeat vector (2,1) of the second one implies θ L = θ R = θ = 10.9 • (d ≈ 0.65 nm) and its interface region includes pentagon-heptagon pairs. 6,17 We would like to note that while we study two representative GBs, (2,0) and (2,1) (corresponding to aligned and misaligned crystallographic orientations), we believe that our findings are generic and remain valid for other GBs in graphene.…”

“…[12][13][14][15] This provides a strong motivation for investigation of morphological, electronic, and spin properties of GBs. A number of studies have been recently reported addressing the band structure, [16][17][18][19][20] spin polarization, 16,17,21,22 electron transport and scattering 12,13,20 in GBs. However, all these studies were limited to the case of electrically neutral graphene, and very little is presently known on how the electronic and transport properties of GBs are modified at nonzero electron densities (i.e., away from the Dirac point).…”