Intercell moiré exciton complexes in electron lattices

Xi Wang; Xiaowei Zhang; Jiayi Zhu; Heonjoon Park; Yingqi Wang; Chong Wang; William G Holtzmann; Takashi Taniguchi; Kenji Watanabe; Jiaqiang Yan; Daniel R Gamelin; Wang Yao; Di Xiao; Ting Cao; Xiaodong Xu

doi:10.1038/s41563-023-01496-2

Intercell moiré exciton complexes in electron lattices

Nat Mater. 2023 May;22(5):599-604. doi: 10.1038/s41563-023-01496-2. Epub 2023 Mar 9.

Authors

Xi Wang^#^{1

2}, Xiaowei Zhang^#³, Jiayi Zhu^#¹, Heonjoon Park^#¹, Yingqi Wang¹, Chong Wang³, William G Holtzmann¹, Takashi Taniguchi⁴, Kenji Watanabe⁵, Jiaqiang Yan⁶, Daniel R Gamelin², Wang Yao^{7

8}, Di Xiao^{9

10

11}, Ting Cao¹², Xiaodong Xu^{13

14}

Affiliations

¹ Department of Physics, University of Washington, Seattle, WA, USA.
² Department of Chemistry, University of Washington, Seattle, WA, USA.
³ Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA.
⁴ International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan.
⁵ Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan.
⁶ Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
⁷ Department of Physics, University of Hong Kong, Hong Kong, China. wangyao@hku.hk.
⁸ HKU-UCAS Joint Institute of Theoretical and Computational Physics at Hong Kong, Hong Kong, China. wangyao@hku.hk.
⁹ Department of Physics, University of Washington, Seattle, WA, USA. dixiao@uw.edu.
¹⁰ Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA. dixiao@uw.edu.
¹¹ Pacific Northwest National Laboratory, Richland, WA, USA. dixiao@uw.edu.
¹² Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA. tingcao@uw.edu.
¹³ Department of Physics, University of Washington, Seattle, WA, USA. xuxd@uw.edu.
¹⁴ Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA. xuxd@uw.edu.

^# Contributed equally.

PMID: 36894775
DOI: 10.1038/s41563-023-01496-2

Abstract

Excitons, Coulomb-bound electron-hole pairs, play a crucial role in both optical excitation and correlated phenomena in solids. When excitons interact with other quasiparticles, few- and many-body excited states can appear. Here we report an interaction between exciton and charges enabled by unusual quantum confinement in two-dimensional moiré superlattices, which results in many-body ground states composed of moiré excitons and correlated electron lattices. In an H-stacked (60^o-twisted) WS₂/WSe₂ heterobilayer, we found an interlayer moiré exciton whose hole is surrounded by its partner electron's wavefunction distributed among three adjacent moiré traps. This three-dimensional excitonic structure enables large in-plane electrical quadrupole moments in addition to the vertical dipole. Upon doping, the quadrupole facilitates the binding of interlayer moiré excitons to the charges in neighbouring moiré cells, forming intercell charged exciton complexes. Our work provides a framework for understanding and engineering emergent exciton many-body states in correlated moiré charge orders.

Abstract

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