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Title
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Ballistic electron channels including weakly protected topological states in delaminated bilayer graphene
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Author
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Abstract
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| We show that delaminations in bilayer graphene (BLG) with electrostatically induced interlayer symmetry 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-polarized 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 stackings in BLGs on the left and right of the delamination (AB-2ML-BA or BA-2ML-AB, where 2ML indicates two decoupled monolayers of graphene), the lowest-energy ballistic channels are gapless, have linear dispersion, and appear to be weakly topologically protected. When BLG stackings on both sides of the delamination are the same (AB-2ML-AB or BA-2ML-BA), the lowest-energy ballistic channels are gapped, with a gap epsilon(g) scaling as epsilon(g) alpha W-1 with delamination width and epsilon(g) alpha delta(-1) with the on-layer energy difference in the delaminated part of the structure. Depending on the width, delaminations may also support several "higher-energy" waveguide modes. Our results are based on both the analytical study of the wave matching of Dirac states and tight-binding model calculations, and we analyze in detail the dependence of the delamination spectrum on the electrostatic conditions in the structure, such as the vertical displacement field. |
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Language
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English
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Source (journal)
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Physical review B / American Physical Society. - New York, N.Y, 2016, currens
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Publication
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New York, N.Y
:
American Physical Society
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2018
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ISSN
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2469-9969
[online]
2469-9950
[print]
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DOI
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10.1103/PHYSREVB.97.045301
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Volume/pages
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97
:4
(2018)
, 12 p.
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Article Reference
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045301
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ISI
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000419772200005
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Medium
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E-only publicatie
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Full text (Publisher's DOI)
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Full text (open access)
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