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Exciton fine structure in twisted transition metal dichalcogenide heterostructures

Kundu, S and Amit, T and Krishnamurthy, HR and Jain, M and Refaely-Abramson, S (2023) Exciton fine structure in twisted transition metal dichalcogenide heterostructures. In: npj Computational Materials, 9 (1).

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Official URL: https://www.nature.com/articles/s41524-023-01145-x


Moiré superlattices of transition metal dichalcogenide (TMD) heterostructures give rise to rich excitonic phenomena associated with the interlayer twist angle. Theoretical calculations of excitons in such systems are typically based on model moiré potentials that mitigate the computational cost. However, predictive understanding of the electron-hole coupling dominating the excitations is crucial to realize the twist-induced modifications of the optical selection rules. In this work, we use many-body perturbation theory to evaluate the relation between twist angle and exciton properties in TMD heterostructures. We present an approach for unfolding excitonic states from the moiré Brillouin zone onto the separate-layer ones. Applying this method to a large-angle twisted MoS2/MoSe2 bilayer, we find that the optical spectrum is dominated by mixed electron–hole transitions with different momenta in the separate monolayers, leading to unexpected hybridization between interlayer and intralayer excitons. Our findings offer a design pathway for exciton layer-localization in TMD heterostructures. © 2023, Springer Nature Limited.

Item Type: Journal Article
Publication: npj Computational Materials
Publisher: Nature Research
Additional Information: The copyright for this article belongs to Authors.
Keywords: Computation theory; Layered semiconductors; Molybdenum compounds; Perturbation techniques; Transition metals, Computational costs; Electron hole; Exciton fine structure; Excitonic phenomena; Excitons properties; Many body perturbation theory; Optical selection rules; Theoretical calculations; Transition metal dichalcogenides (TMD); Twist angles, Excitons
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 30 Nov 2023 07:11
Last Modified: 30 Nov 2023 07:11
URI: https://eprints.iisc.ac.in/id/eprint/83351

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