Quantum Transport in Graphene Nanoribbons with Realistic Edges

Hawkins, Patrick; Begliarbekov, Milan; Živković, Marko; Strauf, Stefan; Search, Christopher P.

doi:10.1021/jp304676h

Cited by 16 publications

(22 citation statements)

References 37 publications

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“…86,87 More complicated reconstructions show a change in the number of carbon atoms in the outermost rings. 85,[88][89][90][91][92] A small selection of such edge reconstructions with a changed number of carbon atoms per ring is shown in Fig. 6.…”

Section: B Reconstructed Edgesmentioning

confidence: 99%

“…85 Reconstructed edges where the outermost carbon atoms are passivated by hydrogen were further investigated. 88 Many of these edge configurations have similar energies 85,88,90,92 such that it is hard to predict which type of edge will be prevalent in experiments. It is therefore likely that different fabrication techniques will result in different edges.…”

Section: B Reconstructed Edgesmentioning

confidence: 99%

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Localized charge carriers in graphene nanodevices

Bischoff

Varlet

Simonet

et al. 2015

Applied Physics Reviews

100

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Graphene—two-dimensional carbon—is a material with unique mechanical, optical, chemical, and electronic properties. Its use in a wide range of applications was therefore suggested. From an electronic point of view, nanostructured graphene is of great interest due to the potential opening of a band gap, applications in quantum devices, and investigations of physical phenomena. Narrow graphene stripes called “nanoribbons” show clearly different electronical transport properties than micron-sized graphene devices. The conductivity is generally reduced and around the charge neutrality point, the conductance is nearly completely suppressed. While various mechanisms can lead to this observed suppression of conductance, disordered edges resulting in localized charge carriers are likely the main cause in a large number of experiments. Localized charge carriers manifest themselves in transport experiments by the appearance of Coulomb blockade diamonds. This review focuses on the mechanisms responsible for this charge localization, on interpreting the transport details, and on discussing the consequences for physics and applications. Effects such as multiple coupled sites of localized charge, cotunneling processes, and excited states are discussed. Also, different geometries of quantum devices are compared. Finally, an outlook is provided, where open questions are addressed.

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Section: B Reconstructed Edgesmentioning

confidence: 99%

Section: B Reconstructed Edgesmentioning

confidence: 99%

Localized charge carriers in graphene nanodevices

Bischoff

Varlet

Simonet

et al. 2015

Applied Physics Reviews

100

View full text Add to dashboard Cite

show abstract

“…Other possible edge reconstructions, see e.g. [30][31][32], are not considered here. Note that the orientation of the graphene lattice with respect to the used coordinate system is not changed in the two stripes.…”

Section: Systemmentioning

confidence: 99%

“…Thus, at the edge the wave function has to vanish only on one sublattice, while the surface state resides on the other sublattice. At an armchair edge atoms from both sublattices appear and a surface state is not possible, see [3,31,49,50] for details. However, in figure 3 the DOS of the armchair stripe is also nonzero at E = 0.…”

Section: Density Of Statesmentioning

confidence: 99%

Edge magnetotransport in graphene: A combined analytical and numerical study

Stegmann

Lorke

2015

Annalen der Physik

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The current flow along the boundary of graphene stripes in a perpendicular magnetic field is studied theoretically by the nonequilibrium Green's function method. In the case of specular reflections at the boundary, the Hall resistance shows equidistant peaks, which are due to classical cyclotron motion. When the strength of the magnetic field is increased, anomalous resistance oscillations are observed, similar to those found in a nonrelativistic 2D electron gas [New. J. Phys. 15:113047 (2013)]. Using a simplified model, which allows to solve the Dirac equation analytically, the oscillations are explained by the interference between the occupied edge states causing beatings in the Hall resistance. A rule of thumb is given for the experimental observability. Furthermore, the local current flow in graphene is affected significantly by the boundary geometry. A finite edge current flows on armchair edges, while the current on zigzag edges vanishes completely. The quantum Hall staircase can be observed in the case of diffusive boundary scattering. The number of spatially separated edge channels in the local current equals the number of occupied Landau levels. The edge channels in the local density of states are smeared out but can be made visible if only a subset of the carbon atoms is taken into account.

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“…The hopping coefficients on the carbon hexagon edges is t 0 which is usually equal to 2.7eV , while those on the deformed bonds belonging to heptagons or pentagons are taken from Refs. [12] as shown in Fig. 1 and Tab.…”

Section: Model and Methodsmentioning

confidence: 85%

Electronic Transport Through Graphene Nanoribbons with Stone-Wales Reconstruction at Edges and Interfaces

Wang¹,

Zhang²,

Ye³

et al. 2016

j nanosci nanotechnol

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In this paper, we study the conductance of the graphene nanoribbons(GNRs) in the presence of the Stone-Wales(S-W) reconstruction, using the transfer matrix method. The ribbon is connected with semi-infinite quantum wires as the leads. The S-W reconstruction occurs on the edges and the interfaces between the electrodes and ribbon. When the reconstruction occurs on the edges, the conductance is suppressed considerably if the gate voltage Vg takes intermediate values around |Vg| ∼ t0(t0 being the hopping amplitude of grahene) in both positive and negative energy regions. In contrast, if Vg is close to the Dirac point or the band edges, the conductance is relatively insensitive to the edge reconstruction. The effect of edge reconstruction become less important with increasing ribbon width as expected. The S-W reconstruction occurs also possibly at the interfaces. In this case, the reconstruction suppresses identically the conductance in the entire range of Vg for armchair GNRs. For the zigzag GNRs, the conductance is strongly suppressed in the negative energy region, however the change of the conductance is relatively small in the positive energy region. We also analyze the transmission coefficients as functions of the channel index(the transverse momentum ky of the leads) for the neutral armchair GNRs with interface defects. Interestingly, there are two transmission peaks appearing at ky = π/3 and ky = 2π/3 due to the unit cell doubling.

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Quantum Transport in Graphene Nanoribbons with Realistic Edges

Cited by 16 publications

References 37 publications

Localized charge carriers in graphene nanodevices

Localized charge carriers in graphene nanodevices

Edge magnetotransport in graphene: A combined analytical and numerical study

Electronic Transport Through Graphene Nanoribbons with Stone-Wales Reconstruction at Edges and Interfaces

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