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

• Published in: Nature communications Vol. 12; no. 1; pp. 3608 - 6
• Main Authors: Miao, Shengnan, Wang, Tianmeng, Huang, Xiong, Chen, Dongxue, Lian, Zhen, Wang, Chong, Blei, Mark, Taniguchi, Takashi, Watanabe, Kenji, Tongay, Sefaattin, Wang, Zenghui, Xiao, Di, Cui, Yong-Tao, Shi, Su-Fei
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 14.06.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301/119/1000/1018; 639/624/1107/527/1819; 639/925/357/1018; Chalcogenides; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; Correlation; Electron states; Electrons; Energy; Engineering; Excitons; Graphene; Humanities and Social Sciences; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Interlayers; Luminescence; MATERIALS SCIENCE; Microscopy; multidisciplinary; Photoluminescence; Photons; Physics; Science; Science (multidisciplinary); Strong interactions (field theory); Superlattices; Transition metal compounds; Tungsten disulfide
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-23732-6

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. Heterobilayers of transition metal dichalcogenides host moiré superlattices that give rise to strong electron interactions. Here, the authors study the photoluminescence from interlayer excitons in a WS 2 /WSe 2 heterobilayer to reveal the onset of various correlated insulating states.