Interlayer valley excitons in heterobilayers of transition metal dichalcogenides


Stacking different two-dimensional crystals into van der Waals heterostructures provides an exciting approach to designing quantum materials that can harness and extend the already fascinating properties of the constituents. Heterobilayers of transition metal dichalcogenides are particularly attractive for low-dimensional semiconductor optics because they host interlayer excitons—with electrons and holes localized in different layers—which inherit valley-contrasting physics from the monolayers and thereby possess various novel and appealing properties compared to other solid-state nanostructures. This Review presents the contemporary experimental and theoretical understanding of these interlayer excitons. We discuss their unique optical properties arising from the underlying valley physics, the strong many-body interactions and electrical control resulting from the electric dipole moment, and the unique effects of a moiré superlattice on the interlayer exciton potential landscape and optical properties.

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Fig. 1: Heterobilayers of monolayer transition metal dichalcogenides.
Fig. 2: Interlayer excitons and charge transfer in TMD heterobilayers.
Fig. 3: Interlayer valley exciton properties.
Fig. 4: Exciton–exciton interactions.
Fig. 5: Moiré landscape for interlayer excitons.


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Work at the University of Washington was supported by the Department of Energy, Basic Energy Sciences, Materials Sciences and Engineering Division (DE-SC0018171). Work at HKU is supported by the Croucher Foundation (Croucher Innovation Award), UGC (AoE/P-04/08) and RGC (HKU17312916) of HKSAR. X.X. acknowledges the support from the State of Washington funded Clean Energy Institute and from the Boeing Distinguished Professorship in Physics.

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Correspondence to Wang Yao or Xiaodong Xu.

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Rivera, P., Yu, H., Seyler, K.L. et al. Interlayer valley excitons in heterobilayers of transition metal dichalcogenides. Nature Nanotech 13, 1004–1015 (2018) doi:10.1038/s41565-018-0193-0

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