Suppressed conductance in a metallic graphene nanojunction

National Laboratory of Superhard Materials, Department of Physics, Jilin University, Changchun 130023, China
Journal of Applied Physics (Impact Factor: 2.21). 02/2009; DOI: 10.1063/1.3054449
Source: IEEE Xplore

ABSTRACT The linear conductance spectrum of a metallic graphene junction formed by interconnecting two gapless graphene nanoribbons is calculated. A strong conductance suppression appears in the vicinity of the Dirac point. We found that such a conductance suppression arises from the antiresonance effect associated with an edge state localized at the zigzag-edged shoulder of the junction. The conductance valley due to the antiresonance is rather robust in the presence of the impurity and vacancy scattering. Also the center of the conductance valley can be readily tuned by an electric field exerted on the wider nanoribbon.

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    ABSTRACT: Based on the nearest-neighbor tight-binding model, we present analytical description of single-mode electron transport through a common-edged junction connecting two semimetal armchair ribbons of different width. The results obtained demonstrate the transmission suppression in the vicinity of the neutrality point except for the junction of the ribbons consisting of 3p-1 and 3p+2 dimer lines, p is odd. Unlike other interconnections, this junction is shown to be free of local levels arising at the junction interface and exhibits electron backscattering to be inversely as the square of 2p+1. We also demonstrate that non-zero propagation through a graphene junction can be described by the same relation as that for linear undimerized chain of atoms with one defect bond.
    Physics of Condensed Matter 01/2009; 72(2):203-209. · 1.28 Impact Factor


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