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Updated: Jul 13, 2026

Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
Published on: July 24, 2015
Perfectly conducting channel and universality crossover in disordered graphene nanoribbons
Katsunori Wakabayashi1, Yositake Takane, Manfred Sigrist
1Department of Quantum Matter, AdSM, Hiroshima University, Higashi-Hiroshima 739-8530, Japan.
Abstract:
The band structure of graphene ribbons with zigzag edges have two valleys well separated in momentum space, related to the two Dirac points of the graphene spectrum. The propagating modes in each valley contain a single chiral mode originating from a partially flat band at the band center. This feature gives rise to a perfectly conducting channel in the disordered system, if the impurity scattering does not connect the two valleys, i.e., for long-range impurity potentials. Ribbons with short-range impurity potentials, however, through intervalley scattering display ordinary localization behavior. The two regimes belong to different universality classes: unitary for long-range impurities and orthogonal for short-range impurities.
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