Strong and tunable interlayer coupling of infrared-active phonons to excitons in van der Waals heterostructures

Luojun Du*, Yanchong Zhao, Zhiyan Jia, Mengzhou Liao, Qinqin Wang, Xiangdong Guo, Zhiwen Shi, Rong Yang, Kenji Watanabe, Takashi Taniguchi, Jianyong Xiang, Dongxia Shi, Qing Dai, Zhipei Sun, Guangyu Zhang

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

6 Citations (Scopus)
247 Downloads (Pure)

Abstract

Understanding and manipulating the quantum interlayer exciton-phonon coupling in van der Waals heterostructures, especially for infrared active phonons with electromagnetic fields, would set a foundation for realizing exotic quantum phenomena and optoelectronic applications. Here we report experimental observations of strong mutual interactions between infrared active phonons in hexagonal boron nitride (hBN) and excitons in WS2. Our results underscore that the infrared active A2u mode of hBN becomes Raman active with strong intensities in WS2/hBN heterostructures through resonant coupling to the B exciton of WS2. Moreover, we demonstrate that the activated A2u phonon of hBN can be tuned by the hBN thickness and harbors a striking anticorrelation intensity modulation, as compared with the optically silent B1g mode. Our observation of the interlayer exciton-infrared active phonon interactions and their evolution with hBN thickness provide a firm basis for engineering the hyperbolic exciton-phonon polaritons, chiral phonons and fascinating nanophotonics based on van der Waals heterostructures.

Original languageEnglish
Article number205410
Number of pages9
JournalPhysical Review B
Volume99
Issue number20
DOIs
Publication statusPublished - 10 May 2019
MoE publication typeA1 Journal article-refereed

Keywords

  • VALLEY POLARIZATION
  • MONOLAYER MOS2
  • BORON-NITRIDE
  • POLARITONS
  • GRAPHENE
  • TRANSPORT
  • MODES
  • WS2

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