Every-other-layer dipolar excitons in a spin-valley locked superlattice

Yinong Zhang, Chengxin Xiao, Dmitry Ovchinnikov, Jiayi Zhu, Xi Wang, Takashi Taniguchi, Kenji Watanabe, Jiaqiang Yan, Wang Yao, Xiaodong Xu

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Monolayer semiconducting transition metal dichalcogenides possess broken inversion symmetry and strong spin-orbit coupling, leading to a unique spin-valley locking effect. In 2H stacked pristine multilayers, spin-valley locking yields an electronic superlattice structure, where alternating layers correspond to barriers and quantum wells depending on the spin-valley indices. Here we show that the spin-valley locked superlattice hosts a kind of dipolar exciton with the electron and hole constituents separated in an every-other-layer configuration: that is, either in two even or two odd layers. Such excitons become optically bright via hybridization with intralayer excitons. This effect is also manifested by the presence of multiple anti-crossing patterns in the reflectance spectra, as the dipolar exciton is tuned through the intralayer resonance by an electric field. The reflectance spectra further reveal an excited state orbital of the every-other-layer exciton, pointing to a sizable binding energy in the same order of magnitude as the intralayer exciton. As layer thickness increases, the dipolar exciton can form a one-dimensional Bose–Hubbard chain displaying layer number-dependent fine spectroscopy structures.

Original languageEnglish
Pages (from-to)501-506
Number of pages6
JournalNature Nanotechnology
Volume18
Issue number5
DOIs
StatePublished - May 2023

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