Twist-angle dependent dehybridization of momentum-indirect excitons in MoSe2/MoS2 heterostructures

The moire superlattice has emerged as a powerful way to tune excitonic properties in two-dimensional van der Waals structures. However, the current understanding of the influence of the twist angle for interlayer excitons (IXs) in heterostructures is mainly limited to momentum-direct K-K transitions. In this work, we use a judicious combination of spectroscopy and many-particle theory to investigate the influence of the twist angle on momentum-indirect IXs of a MoSe2/MoS2 heterostructure. Here, the energetically lowest state is a dark and strongly hybridized Gamma K exciton. We show that increasing the twist angle from an aligned structure (0(circle) or 60(circle)) gives rise to a large blue shift of the IX, which is a manifestation of the strong dehybridization of this state. Moreover, for small twist angle heterostructures, our photoluminescence measurements reveal contributions from two IX states, which our modelling attributes to transitions from different moire minibands. Our finding contributes to a better fundamental understanding of the influence of the moire pattern on the hybridization of momentum-dark IX states, which may be important for applications in moire-tronics including novel quantum technologies.

Automated summary

In this study, the influence of twist angle on momentum-indirect excitons (IXs) in a MoSe2/MoS2 heterostructure was investigated using spectroscopy and many-particle theory. It was found that increasing the twist angle led to a significant blue shift of the excitons due to dehybridization. Furthermore, for small twist angle heterostructures, two IX states were observed through photoluminescence measurements, which were attributed to transitions from different moire minibands. This research contributes to a better understanding of the hybridization of momentum-dark IX states influenced by the moire pattern, which is important for applications in moire-tronics and quantum technologies.