Atomistic theory of twist-angle dependent intralayer and interlayer exciton properties in twisted bilayer materials
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arXiv
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| Hauptverfasser: | , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866915193175408640 |
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| author | Maity, Indrajit Mostofi, Arash A. Lischner, Johannes |
| author_facet | Maity, Indrajit Mostofi, Arash A. Lischner, Johannes |
| contents | Twisted bilayers of two-dimensional (2D) materials have emerged as a highly tunable platform to study and engineer properties of excitons. However, the atomistic description of these properties has remained a significant challenge as a consequence of the large unit cells of the emergent moiré superlattices. To address this problem, we introduce an efficient approach to solve the Bethe-Salpeter equation that exploits the localization of atomic Wannier functions. We then use this approach to study intra- and interlayer excitons in twisted WS$_{2}$/WSe$_{2}$ at a range of twist angles. In agreement with experiment, we find that the optical spectrum exhibits three low-energy peaks for twist angles small than $2^\circ$. The energy splitting between the peaks is described accurately. We also find two low-energy interlayer excitons with weak oscillator strengths. Our approach opens up new opportunities for the design of light-matter interactions in ultrathin materials. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2406_11098 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Atomistic theory of twist-angle dependent intralayer and interlayer exciton properties in twisted bilayer materials Maity, Indrajit Mostofi, Arash A. Lischner, Johannes Materials Science Twisted bilayers of two-dimensional (2D) materials have emerged as a highly tunable platform to study and engineer properties of excitons. However, the atomistic description of these properties has remained a significant challenge as a consequence of the large unit cells of the emergent moiré superlattices. To address this problem, we introduce an efficient approach to solve the Bethe-Salpeter equation that exploits the localization of atomic Wannier functions. We then use this approach to study intra- and interlayer excitons in twisted WS$_{2}$/WSe$_{2}$ at a range of twist angles. In agreement with experiment, we find that the optical spectrum exhibits three low-energy peaks for twist angles small than $2^\circ$. The energy splitting between the peaks is described accurately. We also find two low-energy interlayer excitons with weak oscillator strengths. Our approach opens up new opportunities for the design of light-matter interactions in ultrathin materials. |
| title | Atomistic theory of twist-angle dependent intralayer and interlayer exciton properties in twisted bilayer materials |
| topic | Materials Science |
| url | https://arxiv.org/abs/2406.11098 |