  The role of defect-induced zero-energy modes on charge transport in graphene
is investigated using Kubo and Landauer transport calculations. By tuning the
density of random distributions of monovacancies either equally populating the
two sublattices or exclusively located on a single sublattice, all conduction
regimes are covered from direct tunneling through evanescent modes to
mesoscopic transport in bulk disordered graphene. Depending on the transport
measurement geometry, defect density, and broken sublattice-symmetry, the Dirac
point conductivity is either exceptionally robust against disorder
(supermetallic state) or suppressed through a gap opening or by algebraic
localization of zero-energy modes, whereas weak localization and the Anderson
insulating regime are obtained for higher energies. These findings clarify the
contribution of zero-energy modes to transport at the Dirac point, hitherto
controversial.
