title: Infrared nanoscopy of dirac plasmons at the graphene-SiO₂ interface.
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.
authors.affiliation: Department of Physics, University of California San Diego, La Jolla, California 92093, United States. zfei@physics.ucsd.edu
authors.forename: Zhe
authors.initials: Z
authors.lastname: Fei
authors.forename: Gregory O
authors.initials: GO
authors.lastname: Andreev
authors.forename: Wenzhong
authors.initials: W
authors.lastname: Bao
authors.forename: Lingfeng M
authors.initials: LM
authors.lastname: Zhang
authors.forename: Alexander
authors.initials: A
authors.lastname: S McLeod
authors.forename: Chen
authors.initials: C
authors.lastname: Wang
authors.forename: Margaret K
authors.initials: MK
authors.lastname: Stewart
authors.forename: Zeng
authors.initials: Z
authors.lastname: Zhao
authors.forename: Gerardo
authors.initials: G
authors.lastname: Dominguez
authors.forename: Mark
authors.initials: M
authors.lastname: Thiemens
authors.forename: Michael M
authors.initials: MM
authors.lastname: Fogler
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Tauber
authors.forename: Antonio H
authors.initials: AH
authors.lastname: Castro-Neto
authors.forename: Chun Ning
authors.initials: CN
authors.lastname: Lau
authors.forename: Fritz
authors.initials: F
authors.lastname: Keilmann
authors.forename: Dimitri N
authors.initials: DN
authors.lastname: Basov
mesh_terms: D003198:Computer Simulation; D006108:Graphite / Q000737:chemistry* / Q000528:radiation effects*; D007259:Infrared Rays; D008422:Materials Testing; D008956:Models, Chemical; D049329:Nanostructures / Q000737:chemistry* / Q000528:radiation effects*; D010316:Particle Size; D012822:Silicon Dioxide / Q000737:chemistry* / Q000528:radiation effects*; D020349:Surface Plasmon Resonance / Q000379:methods*
chemical_list: D012822:Silicon Dioxide; D006108:Graphite