Wallauer, Robert and Perea-Causin, Raul and Muenster, Lasse and Zajusch, Sarah and Brem, Samuel and Guedde, Jens and Tanimura, Katsumi and Lin, Kai-Qiang and Huber, Rupert and Malic, Ermin and Hoefer, Ulrich (2021) Momentum-Resolved Observation of Exciton Formation Dynamics in Monolayer WS2. NANO LETTERS, 21 (13). pp. 5867-5873. ISSN 1530-6984, 1530-6992
Full text not available from this repository. (Request a copy)Abstract
The dynamics of momentum-dark exciton formation in transition metal dichalcogenides is difficult to measure experimentally, as many momentum-indirect exciton states are not accessible to optical interband spectroscopy. Here, we combine a tunable pump, high-harmonic probe laser source with a 3D momentum imaging technique to map photoemitted electrons from monolayer WS2. This provides momentum-, energy- and time-resolved access to excited states on an ultrafast time scale. The high temporal resolution of the setup allows us to trace the early-stage exciton dynamics on its intrinsic time scale and observe the formation of a momentum-forbidden dark KS exciton a few tens of femtoseconds after optical excitation. By tuning the excitation energy, we manipulate the temporal evolution of the coherent excitonic polarization and observe its influence on the dark exciton formation. The experimental results are in excellent agreement with a fully microscopic theory, resolving the temporal and spectral dynamics of bright and dark excitons in WS2.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | SCATTERING; SPACE; transition metal dichalcogenides; monolayers; dark excitons; exciton dynamics; exciton band structure; trARPES |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Experimental and Applied Physics > Chair Professor Huber > Group Rupert Huber |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 14 Sep 2022 09:33 |
| Last Modified: | 14 Sep 2022 09:33 |
| URI: | https://pred.uni-regensburg.de/id/eprint/47450 |
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