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/WS2moiré superlattice by changing WSe2from 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/WS2interface. In addition, the energy resonances of moiré excitons are strongly modified, with their separation significantly increased in multilayer WSe2/monolayer WS2moiré superlattice. The additional WSe2layers also modulate the strong electronic correlation strength, evidenced by the reduced Mott transition temperature with added WSe2layer(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.
This content will become publicly available on May 18, 2024
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- 2D Materials
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- Medium: X
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- National Science Foundation
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