Infrared nanoscopy of dirac plasmons at the graphene-SiO₂ interface.

Fei, Zhe; Andreev, Gregory O; Bao, Wenzhong; Zhang, Lingfeng M; S McLeod, Alexander; Wang, Chen; Stewart, Margaret K; Zhao, Zeng et al. · Nano Lett · 2011

basic_science · Level V

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Abstract

We report on infrared (IR) nanoscopy of 2D plasmon excitations of Dirac fermions in graphene. This is achieved by confining mid-IR radiation at the apex of a nanoscale tip: an approach yielding 2 orders of magnitude increase in the value of in-plane component of incident wavevector q compared to free space propagation. At these high wavevectors, the Dirac plasmon is found to dramatically enhance the near-field interaction with mid-IR surface phonons of SiO(2) substrate. Our data augmented by detailed modeling establish graphene as a new medium supporting plasmonic effects that can be controlled by gate voltage.

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