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arXiv · 1911.02848

Gate tunable optical absorption and band structure of twisted bilayer graphene

Kwangnam Yu·Van Luan Nguyen·Tae Soo Kim·Jiwon Jeon·Jiho Kim·Pilkyung Moon·Young Hee Lee·E. J. Choi
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Abstract

We report the infrared transmission measurement on electrically gated twisted bilayer graphene. The optical absorption spectrum clearly manifests the dramatic changes such as the splitting of inter-linear-band absorption step, the shift of inter-van Hove singularity transition peak, and the emergence of very strong intra-valence (intra-conduction) band transition. These anomalous optical behaviors demonstrate consistently the non-rigid band structure modification created by the ion-gel gating through the layer-dependent Coulomb screening. We propose that this screening-driven band modification is an universal phenomenon that persists to other bilayer crystals in general, establishing the electrical gating as a versatile technique to engineer the band structures and to create new types of optical absorptions that can be exploited in electro-optical device application.

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Kwangnam Yu, Van Luan Nguyen, Tae Soo Kim, Jiwon Jeon, Jiho Kim, Pilkyung Moon, Young Hee Lee, E. J. Choi. 2019-11-07. Gate tunable optical absorption and band structure of twisted bilayer graphene. https://doi.org/10.1103/physrevb.99.241405

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