Strong interaction between interlayer excitons and correlated electrons in WSe2/WS2 moiré superlattice

Shengnan Miao; Tianmeng Wang; Xiong Huang; Dongxue Chen; Zhen Lian; Chong Wang; Mark Blei; Takashi Taniguchi; Kenji Watanabe; Sefaattin Tongay; Zenghui Wang; Di Xiao; Yong-Tao Cui; Su-Fei Shi

doi:10.1038/s41467-021-23732-6

Strong interaction between interlayer excitons and correlated electrons in WSe₂/WS₂ moiré superlattice

Nat Commun. 2021 Jun 14;12(1):3608. doi: 10.1038/s41467-021-23732-6.

Authors

Shengnan Miao^#¹, Tianmeng Wang^#¹, Xiong Huang^#^{2

3}, Dongxue Chen^#^{1

4}, Zhen Lian¹, Chong Wang⁵, Mark Blei⁶, Takashi Taniguchi⁷, Kenji Watanabe⁸, Sefaattin Tongay⁶, Zenghui Wang⁹, Di Xiao⁵, Yong-Tao Cui¹⁰, Su-Fei Shi^{11

12}

Affiliations

¹ Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA.
² Department of Physics and Astronomy, University of California, Riverside, CA, USA.
³ Department of Materials Science and Engineering, University of California, Riverside, CA, USA.
⁴ Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, Sichuan, China.
⁵ Department of Physics, Carnegie Mellon University, Pittsburgh, PA, USA.
⁶ School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, USA.
⁷ Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan.
⁸ International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan.
⁹ Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, Sichuan, China. zenghui.wang@uestc.edu.cn.
¹⁰ Department of Physics and Astronomy, University of California, Riverside, CA, USA. yongtao.cui@ucr.edu.
¹¹ Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA. shis2@rpi.edu.
¹² Department of Electrical, Computer and Systems Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA. shis2@rpi.edu.

^# Contributed equally.

Abstract

Heterobilayers of transition metal dichalcogenides (TMDCs) can form a moiré superlattice with flat minibands, which enables strong electron interaction and leads to various fascinating correlated states. These heterobilayers also host interlayer excitons in a type-II band alignment, in which optically excited electrons and holes reside on different layers but remain bound by the Coulomb interaction. Here we explore the unique setting of interlayer excitons interacting with strongly correlated electrons, and we show that the photoluminescence (PL) of interlayer excitons sensitively signals the onset of various correlated insulating states as the band filling is varied. When the system is in one of such states, the PL of interlayer excitons is relatively amplified at increased optical excitation power due to reduced mobility, and the valley polarization of interlayer excitons is enhanced. The moiré superlattice of the TMDC heterobilayer presents an exciting platform to engineer interlayer excitons through the periodic correlated electron states.