Publication Date

12-15-2017

Department

Ames Laboratory; Physics and Astronomy; Mechanical Engineering; Industrial and Manufacturing Systems Engineering

Campus Units

Mechanical Engineering, Physics and Astronomy, Ames Laboratory

OSTI ID+

1415834

Report Number

IS-J 9542

DOI

10.1103/PhysRevLett.119.247402

Journal Title

Physical Review Letters

Volume Number

119

First Page

247402

Abstract

We report a systematic plasmonic study of twisted bilayer graphene (TBLG)—two graphene layers stacked with a twist angle. Through real-space nanoimaging of TBLG single crystals with a wide distribution of twist angles, we find that TBLG supports confined infrared plasmons that are sensitively dependent on the twist angle. At small twist angles, TBLG has a plasmon wavelength comparable to that of single-layer graphene. At larger twist angles, the plasmon wavelength of TBLG increases significantly with apparently lower damping. Further analysis and modeling indicate that the observed twist-angle dependence of TBLG plasmons in the Dirac linear regime is mainly due to the Fermi-velocity renormalization, a direct consequence of interlayer electronic coupling. Our work unveils the tailored plasmonic characteristics of TBLG and deepens our understanding of the intriguing nano-optical physics in novel van der Waals coupled two-dimensional materials.

Language

en

Department of Energy Subject Categories

36 MATERIALS SCIENCE

Publisher

Iowa State University Digital Repository, Ames IA (United States)

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