Effect of layered -coupling in twisted WSe2 moire superlattices

Recently, the discovery of a variety of moire-related properties in the twisted vertical stacking of two different monolayers has attracted considerable attention. The introduction of small twist angles in transition metal dichalcogenide (TMD) heterostructures leads to the emergence of moire potentials, which provide a fascinating platform for the study of strong interactions of electrons. While there has been extensive research on moire excitons in twisted bilayer superlattices, the capture and study of moire excitons in homostructure superlattices with layer-coupling effects remain elusive. Here, we present the observation of moire excitons in the twisted 1L-WSe2/1L-WSe2 and 1L-WSe2/2L-WSe2 homostructures with various layer-coupling interactions. The results reveal that the moire potential increases (similar to 260%) as the number of underlying layers decreases, indicating the effect of layer coupling on the modulation of the moire potential. The effects of the temperature and laser power dependence as well as valley polarization on moire excitons were further demonstrated, and the crucial spectral features observed were explained. Our findings pave the way for exploring quantum phenomena and related applications of quantum information.

Automated summary

The recent discovery of various moire-related properties in twisted vertical stacking structures has attracted significant attention, particularly in transition metal dichalcogenide heterostructures. This study presents the observation of moire excitons in homostructures with different layer-coupling interactions, and the results show that reducing the number of underlying layers increases the moire potential. The effects of temperature, laser power, and valley polarization on moire excitons were also investigated, providing insights into their spectral features. These findings pave the way for the exploration of quantum phenomena and related applications in quantum information.