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Twist Angle-Dependent Interlayer Exciton Lifetimes in van der Waals Heterostructures

Choi, J and Florian, M and Steinhoff, A and Erben, D and Tran, K and Kim, DS and Sun, L and Quan, J and Claassen, R and Majumder, S and Hollingsworth, JA and Taniguchi, T and Watanabe, K and Ueno, K and Singh, A and Moody, G and Jahnke, F and Li, X (2021) Twist Angle-Dependent Interlayer Exciton Lifetimes in van der Waals Heterostructures. In: Physical Review Letters, 126 (4).

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Official URL: https://dx.doi.org/10.1103/PhysRevLett.126.047401


In van der Waals (vdW) heterostructures formed by stacking two monolayers of transition metal dichalcogenides, multiple exciton resonances with highly tunable properties are formed and subject to both vertical and lateral confinement. We investigate how a unique control knob, the twist angle between the two monolayers, can be used to control the exciton dynamics. We observe that the interlayer exciton lifetimes in MoSe2/WSe2 twisted bilayers (TBLs) change by one order of magnitude when the twist angle is varied from 1° to 3.5°. Using a low-energy continuum model, we theoretically separate two leading mechanisms that influence interlayer exciton radiative lifetimes. The shift to indirect transitions in the momentum space with an increasing twist angle and the energy modulation from the moiré potential both have a significant impact on interlayer exciton lifetimes. We further predict distinct temperature dependence of interlayer exciton lifetimes in TBLs with different twist angles, which is partially validated by experiments. While many recent studies have highlighted how the twist angle in a vdW TBL can be used to engineer the ground states and quantum phases due to many-body interaction, our studies explore its role in controlling the dynamics of optically excited states, thus, expanding the conceptual applications of "twistronics". © 2021 American Physical Society.

Item Type: Journal Article
Publication: Physical Review Letters
Publisher: American Physical Society
Additional Information: The copyright of this article belongs to American Physical Society
Keywords: Continuum mechanics; Ground state; Monolayers; Quantum theory; Temperature distribution; Transition metals; Van der Waals forces, Exciton radiative lifetimes; Indirect transition; Lateral confinement; Many-body interactions; Optically excited state; Temperature dependence; Transition metal dichalcogenides; Tunable properties, Excitons
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 24 Feb 2021 10:19
Last Modified: 24 Feb 2021 10:19
URI: http://eprints.iisc.ac.in/id/eprint/68012

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