Robust subgap edge conduction in bilayer graphene with disordered edge termination

Abstract

The subgap transport in electrostatically gapped bilayer graphene (BLG) is explored by adopting ultrashort constrictions of BLG. We confirmed the emergence of the edge conducting channels, with a residual conductance of $\ensuremath{\sim}2{e}^{2}/h$ per edge of realistic disorder. Transport along the edge state exhibits either Coulomb blockade oscillations or Fabry-Perot interference, depending on the interfacial transparency between the reservoirs and the edge channel. Both residual conductance and band-gap dependence of the penetration range of the edge state from a constriction edge coincide well with the behavior of the theoretically predicted robust edge conducting channel, which forms irrespective of the degree of edge disorder.