Tuning moiré excitons and correlated electronic states through layer degree of freedom

Dongxue Chen, Zhen Lian, Xiong Huang, Ying Su, Mina Rashetnia, Li Yan, Mark Blei, Takashi Taniguchi, Kenji Watanabe, Sefaattin Tongay, Zenghui Wang, Chuanwei Zhang, Yong Tao Cui, Su Fei Shi

Research output: Contribution to journalArticlepeer-review

Abstract

Moiré coupling in transition metal dichalcogenides (TMDCs) superlattices introduces flat minibands that enable strong electronic correlation and fascinating correlated states, and it also modifies the strong Coulomb-interaction-driven excitons and gives rise to moiré excitons. Here, we introduce the layer degree of freedom to the WSe2/WS2 moiré superlattice by changing WSe2 from monolayer to bilayer and trilayer. We observe systematic changes of optical spectra of the moiré excitons, which directly confirm the highly interfacial nature of moiré coupling at the WSe2/WS2 interface. In addition, the energy resonances of moiré excitons are strongly modified, with their separation significantly increased in multilayer WSe2/monolayer WS2 moiré superlattice. The additional WSe2 layers also modulate the strong electronic correlation strength, evidenced by the reduced Mott transition temperature with added WSe2 layer(s). The layer dependence of both moiré excitons and correlated electronic states can be well described by our theoretical model. Our study presents a new method to tune the strong electronic correlation and moiré exciton bands in the TMDCs moiré superlattices, ushering in an exciting platform to engineer quantum phenomena stemming from strong correlation and Coulomb interaction.

Original languageEnglish (US)
Article number4810
JournalNature communications
Volume13
Issue number1
DOIs
StatePublished - Dec 2022

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • General
  • Physics and Astronomy(all)

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