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arXiv · 2301.11646

Real-space imaging of the tailored plasmons in twisted bilayer graphene

Fengrui Hu·Suprem R Das·Yilong Luan·T. -F. Chung·Yong P. Chen·Zhe Fei
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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.

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Fengrui Hu, Suprem R Das, Yilong Luan, T. -F. Chung, Yong P. Chen, Zhe Fei. 2023-01-26. Real-space imaging of the tailored plasmons in twisted bilayer graphene. https://doi.org/10.1103/physrevlett.119.247402

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