Multiple virtual tunneling of dirac fermions in granular graphene

Alexandre Pachoud, Manu Jaiswal, Yu Wang, Byung Hee Hong, Jong Hyun Ahn, Kian Ping Loh, Barbaros Özyilmaz

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Abstract

Graphene charge carriers behave as massless Dirac fermions, opening the exciting possibility to observe long-range virtual tunneling of electrons in a solid. In granular metals, electron hops arising from series of virtual transitions are predicted to yield observable currents at low-enough temperatures, but to date experimental evidence is lacking. We report on electron transport in granular graphene films self-assembled by hydrogenation of suspended graphene. While the log-conductance shows a characteristic T -1/2 temperature dependence, cooling the samples below 10â€...K drives a triple crossover: a slope break in log-conductance, simultaneous to a substantial increase in magneto-conductance and onset of large mesoscopic conductance fluctuations. These phenomena are signatures of virtual transitions of electrons between distant localized states, and conductance statistics reveal that the high crossover-temperature is due to the Dirac nature of granular graphene charge carriers.

Original languageEnglish
Article number3404
JournalScientific reports
Volume3
DOIs
Publication statusPublished - 2013 Dec 3

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Pachoud, A., Jaiswal, M., Wang, Y., Hong, B. H., Ahn, J. H., Loh, K. P., & Özyilmaz, B. (2013). Multiple virtual tunneling of dirac fermions in granular graphene. Scientific reports, 3, [3404]. https://doi.org/10.1038/srep03404