Ballistic electron channels including weakly protected topological states in delaminated bilayer graphene

Abstract

We show that delaminations in bilayer graphene (BLG) with electrostatically induced interlayer asymmetry can provide one with ballistic channels for electrons with energies inside the electrostatically induced BLG gap. These channels are formed by a combination of valley-polarised evanescent states propagating along the delamination edges (which persist in the presence of a strong magnetic field) and standing waves bouncing between them inside the delaminated region (in a strong magnetic field, these transform into Landau levels in the monolayers). For inverted stacking between BLGs on the left and right of the delamination (AB-2ML-BA or BA-2ML-AB), the lowest energy ballistic channels are gapless, have linear dispersion and appear to be weakly topologically protected. When BLG stacking order on both sides of the delamination is the same (AB-2ML-AB or BA-2ML-BA), the lowest energy ballistic channels are gapped, with gap ${\epsilon }_g$ scaling as ${\epsilon }_g\propto W^{-1}$ with delamination width and as ${\epsilon }_g\propto {\delta }^{-1}$ with the on-layer energy difference within the delamination. Depending on their width, delaminations may also support several `higher energy' waveguide modes. Our results are based on both an analytical study of the wavematching of Dirac states and tight binding model calculations, and we analyse in detail the dependence of the delamination spectrum on electrostatic conditions in the structure, such as the vertical displacement field.

arXiv comment12 pages, 9 figures

References in corpus (22)

• The electronic properties of graphene
• Two-Dimensional Gas of Massless Dirac Fermions in Graphene
• Landau level degeneracy and quantum Hall effect in a graphite bilayer
• Biased bilayer graphene: semiconductor with a gap tunable by electric field effect
• Asymmetry gap in the electronic band structure of bilayer graphene
• The Kernel Polynomial Method
• Selective transmission of Dirac electrons and ballistic magnetoresistance of \textit{n-p} junctions in graphene
• Topological confinement in bilayer graphene
• Boundary conditions for Dirac fermions on a terminated honeycomb lattice
• Gate-controlled topological conducting channels in bilayer graphene
• Direct imaging of topological edge states at a bilayer graphene domain wall
• Electronic Highways in Bilayer Graphene
• Symmetry of boundary conditions of the Dirac equation for electrons in carbon nanotubes
• Transport in gapped bilayer graphene: the role of potential fluctuations
• Transmission through a boundary between monolayer and bilayer graphene
• Electronic transmission through AB-BA domain boundary in bilayer graphene
• Gauge fields and interferometry in folded graphene
• Chiral states in bilayer graphene: magnetic field dependence and gap opening
• Valley filtering using electrostatic potentials in bilayer graphene
• Topologically confined states at corrugations of gated bilayer graphene
• Gate tunable current partition in graphene based topological zero lines
• Cooling of chiral heat transport in the quantum Hall effect graphene

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• Topologically protected gap states and resonances in gated trilayer graphene
• Non-chiral one-dimensional states propagating inside AB/BA domain walls in bilayer graphene
• Single layer graphene with electronic properties as gated bilayer
• Effects of domain walls in bilayer graphene in an external magnetic field
• Gapless states and current control in strongly distorted gated trilayer graphene