Phys. Rev. B 84, 073405 (2011) [6 pages]Coulomb gap in graphene nanoribbonsReceived 14 June 2011; published 19 August 2011 We investigate the density- and temperature-dependent conductance of graphene nanoribbons with varying aspect ratio. Transport is dominated by a chain of quantum dots forming spontaneously due to disorder. Depending on ribbon length, electron density, and temperature, single or multiple quantum dots dominate the conductance. Between conductance resonances, cotunneling transport at the lowest temperatures turns into activated transport at higher temperatures. The density-dependent activation energy resembles the Coulomb gap in a quantitative manner. Individual resonances show signatures of multilevel transport in some regimes, and stochastic Coulomb blockade in others. ©2011 American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevB.84.073405
DOI:
10.1103/PhysRevB.84.073405
PACS:
73.23.-b, 72.80.Vp
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