title: Tunneling Plasmonics in Bilayer Graphene.
abstract: We report experimental signatures of plasmonic effects due to electron tunneling between adjacent graphene layers. At subnanometer separation, such layers can form either a strongly coupled bilayer graphene with a Bernal stacking or a weakly coupled double-layer graphene with a random stacking order. Effects due to interlayer tunneling dominate in the former case but are negligible in the latter. We found through infrared nanoimaging that bilayer graphene supports plasmons with a higher degree of confinement compared to single- and double-layer graphene, a direct consequence of interlayer tunneling. Moreover, we were able to shut off plasmons in bilayer graphene through gating within a wide voltage range. Theoretical modeling indicates that such a plasmon-off region is directly linked to a gapped insulating state of bilayer graphene, yet another implication of interlayer tunneling. Our work uncovers essential plasmonic properties in bilayer graphene and suggests a possibility to achieve novel plasmonic functionalities in graphene few-layers.
authors.affiliation: †Department of Physics, University of California, San Diego, La Jolla, California 92093, United States.
authors.forename: Z
authors.initials: Z
authors.lastname: Fei
authors.affiliation: †Department of Physics, University of California, San Diego, La Jolla, California 92093, United States.
authors.forename: E G
authors.initials: EG
authors.lastname: Iwinski
authors.affiliation: †Department of Physics, University of California, San Diego, La Jolla, California 92093, United States.|‡Graphene Research Centre, National University of Singapore, 117542, Singapore.
authors.forename: G X
authors.initials: GX
authors.lastname: Ni
authors.affiliation: †Department of Physics, University of California, San Diego, La Jolla, California 92093, United States.|§Department of Physics, Boston University, Boston, Massachusetts 02215, United States.
authors.forename: L M
authors.initials: LM
authors.lastname: Zhang
authors.affiliation: ∥Department of Physics and Astronomy, University of California, Riverside, California 92521, United States.
authors.forename: W
authors.initials: W
authors.lastname: Bao
authors.affiliation: §Department of Physics, Boston University, Boston, Massachusetts 02215, United States.
authors.forename: A S
authors.initials: AS
authors.lastname: Rodin
authors.affiliation: ∥Department of Physics and Astronomy, University of California, Riverside, California 92521, United States.
authors.forename: Y
authors.initials: Y
authors.lastname: Lee
authors.affiliation: †Department of Physics, University of California, San Diego, La Jolla, California 92093, United States.
authors.forename: M
authors.initials: M
authors.lastname: Wagner
authors.affiliation: †Department of Physics, University of California, San Diego, La Jolla, California 92093, United States.|⊥Department of Physics, Stony Brook University, Stony Brook, New York 11794, United States.
authors.forename: M K
authors.initials: MK
authors.lastname: Liu
authors.affiliation: †Department of Physics, University of California, San Diego, La Jolla, California 92093, United States.
authors.forename: S
authors.initials: S
authors.lastname: Dai
authors.affiliation: †Department of Physics, University of California, San Diego, La Jolla, California 92093, United States.
authors.forename: M D
authors.initials: MD
authors.lastname: Goldflam
authors.affiliation: #Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States.
authors.forename: M
authors.initials: M
authors.lastname: Thiemens
authors.affiliation: ∇Ludwig-Maximilians-Universität and Center for Nanoscience, 80539 München, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Keilmann
authors.affiliation: ∥Department of Physics and Astronomy, University of California, Riverside, California 92521, United States.
authors.forename: C N
authors.initials: CN
authors.lastname: Lau
authors.affiliation: ‡Graphene Research Centre, National University of Singapore, 117542, Singapore.|§Department of Physics, Boston University, Boston, Massachusetts 02215, United States.
authors.forename: A H
authors.initials: AH
authors.lastname: Castro-Neto
authors.affiliation: †Department of Physics, University of California, San Diego, La Jolla, California 92093, United States.
authors.forename: M M
authors.initials: MM
authors.lastname: Fogler
authors.affiliation: †Department of Physics, University of California, San Diego, La Jolla, California 92093, United States.
authors.forename: D N
authors.initials: DN
authors.lastname: Basov
keywords: Infrared nanoimaging; bilayer graphene; plasmon-off region; plasmons; tunneling