Impurity-assisted tunneling in graphene

The electric conductance of a strip of undoped graphene increases in the presence of a disorder potential, which is smooth on atomic scales. The phenomenon is attributed to impurity-assisted resonant tunneling of massless Dirac fermions. Employing the transfer matrix approach we demonstrate the resonant character of the conductivity enhancement in the presence of a single impurity. We also calculate the two-terminal conductivity for the model with one-dimensional fluctuations of disorder potential by a mapping onto a problem of Anderson localization.Comment: 6 pages, 3 figures, final version, typos corrected, references adde

Tunneling of Dirac electrons through spatial regions of finite mass

We study the tunneling of chiral electrons in graphene through a region wherethe electronic spectrum changes from the usual linear dispersion to a hyperbolic dispersion,due to the presence of a gap. It is shown that contrary to the tunneling through a potentialbarrier, the transmission of electrons is, in this case, smaller than one for normal incidence.This mechanism may be useful for designing electronic devices made of grapheneinfo:eu-repo/semantics/publishedVersio