https://doi.org/10.1140/epjp/s13360-023-03940-3
Regular Article
Moiré interlayer exciton relative and center of mass motions coupling. Effect on 
interlayer exciton THz transitions
1
Laboratoire de Physique des Matériaux, structures et propriétés, Faculté des sciences de Bizerte, Université de Carthage, 7021, Zarzouna, Bizerte, Tunisia
2
Laboratoire de Physique de la Matière Condensée, Faculté des Sciences de Tunis, Université de Tunis El Manar, 2092, El Manar, Tunis, Tunisia
Received:
25
July
2022
Accepted:
27
March
2023
Published online:
8
May
2023
The study of moiré localized interlayer excitons (LIX) has been considered by assuming a continuous and smooth periodic moiré potential impacting only the center of mass motion (COM) [Tran et al. Nature 567:71, 2019, Ruis-Tijerina et al. Phys Rev B 102:195403, 2020]. This approximation is valid for moiré large period and will not be longer appropriate for small one. Here, we report a theoretical investigation of optical properties of moiré localized excitons in transition metal dichalcogenides (TMDs) heterobilayer (hBL). The model is considered for both small and large moiré periods where the potential acts separately on the electron and hole. This leads to a coupling between the COM and relative motion (RM) of the LIX. The impact of this term is high with small moiré period which shifts the 
energy splitting to the TeraHertz range. The optical response of hBL systems is considered by the calculation of the polarizability applied to the description of the excitation of np dark states interlayer exciton. Finally, a good agreement between recent PL interlayer exciton spectra and our calculations is founded.
Houssem Eddine Hannachi and Donia Elmaghraoui have contributed equally to this work.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2023. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
