Rosati, Roberto and Wagner, Koloman and Brem, Samuel and Perea-Causin, Raul and Ziegler, Jonas D. and Zipfel, Jonas and Taniguchi, Takashi and Watanabe, Kenji and Chernikov, Alexey and Malic, Ermin (2021) Non-equilibrium diffusion of dark excitons in atomically thin semiconductors. NANOSCALE, 13 (47). pp. 19966-19972. ISSN 2040-3364, 2040-3372
Full text not available from this repository. (Request a copy)Abstract
Atomically thin semiconductors provide an excellent platform to study intriguing many-particle physics of tightly-bound excitons. In particular, the properties of tungsten-based transition metal dichalcogenides are determined by a complex manifold of bright and dark exciton states. While dark excitons are known to dominate the relaxation dynamics and low-temperature photoluminescence, their impact on the spatial propagation of excitons has remained elusive. In our joint theory-experiment study, we address this intriguing regime of dark state transport by resolving the spatio-temporal exciton dynamics in hBN-encapsulated WSe2 monolayers after resonant excitation. We find clear evidence of an unconventional, time-dependent diffusion during the first tens of picoseconds, exhibiting strong deviation from the steady-state propagation. Dark exciton states are initially populated by phonon emission from the bright states, resulting in creation of hot (unequilibrated) excitons whose rapid expansion leads to a transient increase of the diffusion coefficient by more than one order of magnitude. These findings are relevant for both fundamental understanding of the spatio-temporal exciton dynamics in atomically thin materials as well as their technological application by enabling rapid diffusion.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | DYNAMICS; TRANSPORT; TRIONS; |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Experimental and Applied Physics > Professor Ganichev > Group Sergey Ganichev |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 21 Sep 2022 06:26 |
| Last Modified: | 21 Sep 2022 06:26 |
| URI: | https://pred.uni-regensburg.de/id/eprint/47765 |
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