Dandu, M and Gupta, G and Dasika, P and Watanabe, K and Taniguchi, T and Majumdar, K (2022) Electrically Tunable Localized versus Delocalized Intralayer Moiré Excitons and Trions in a Twisted MoS2Bilayer. In: ACS Nano, 16 (6). pp. 8983-8992.
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Abstract
Moiré superlattice (mSL)-induced sub-bands in twisted van der Waals homo- and heterostructures govern their optical and electrical properties, rendering additional degrees of freedom such as twist angle. Here, we demonstrate the moiré superlattice effects on the intralayer excitons and trions in a twisted bilayer of MoS2 of H-type stacking at marginal twist angles. We identify the emissions from localized and delocalized sub-bands of intralayer moiré excitons and show their electrical modulation by the corresponding trion formation. The electrical control of the oscillator strength of the moiré excitons also results in the strong tunability of resonant Raman scattering. We find that the gate-induced doping significantly modulates the electronic moiré potential; however, leaves the excitonic moiré confinement unaltered. This effect, coupled with variable moiré trap filling by tuning the optical excitation density, allows us to delineate the different phases of localized and delocalized moiré trions. We demonstrate that the moiré excitons exhibit strong valley coherence that changes in a striking nonmonotonic W-shape with gating due to motional narrowing. These observations from the simultaneous electrostatic control of quasiparticle-dependent moiré potential will lead to exciting effects of tunable many-body phenomena in moiré superlattices.
| Item Type: | Journal Article |
|---|---|
| Publication: | ACS Nano |
| Publisher: | American Chemical Society |
| Additional Information: | The copyright for this article belongs to the Authors. |
| Keywords: | Coherent scattering; Degrees of freedom (mechanics); Excitons; Layered semiconductors; Molybdenum compounds; Sulfur compounds; Van der Waals forces, Bi-layer; Electrically tunable; Intra-layer; Localised; Moire; Subbands; Trion; Twist angles; Twisted bilayers; Valley coherence, Raman scattering |
| Department/Centre: | Division of Electrical Sciences > Electrical Communication Engineering |
| Date Deposited: | 10 Aug 2022 05:53 |
| Last Modified: | 10 Aug 2022 05:53 |
| URI: | https://eprints.iisc.ac.in/id/eprint/75785 |
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