Dark exciton-exciton annihilation in monolayer WSe2
Journal article, 2021
The exceptionally strong Coulomb interaction in semiconducting transition-metal dichalcogenides (TMDs) gives rise to a rich exciton landscape consisting of bright and dark exciton states. At elevated densities, excitons can interact through exciton-exciton annihilation (EEA), an Auger-like recombination process limiting the efficiency of optoelectronic applications. Although EEA is a well-known and particularly important process in atomically thin semiconductors determining exciton lifetimes and affecting transport at elevated densities, its microscopic origin has remained elusive. In this joint theory-experiment study combining microscopic and material-specific theory with time- and temperature-resolved photoluminescence measurements, we demonstrate the key role of dark intervalley states that are found to dominate the EEA rate in monolayer WSe2. We reveal an intriguing, characteristic temperature dependence of Auger scattering in this class of materials with an excellent agreement between theory and experiment. Our study provides microscopic insights into the efficiency of technologically relevant Auger scattering channels within the remarkable exciton landscape of atomically thin semiconductors.
Author
Daniel Erkensten
Chalmers, Physics, Condensed Matter and Materials Theory
Samuel Brem
Philipps University Marburg
Koloman Wagner
Technische Universität Dresden
University of Regensburg
Roland Gillen
University of Erlangen-Nuremberg (FAU)
Raul Perea Causin
Chalmers, Physics, Condensed Matter and Materials Theory
2D-Tech
Jonas D. Ziegler
Technische Universität Dresden
University of Regensburg
Takashi Taniguchi
National Institute for Materials Science (NIMS)
Kenji Watanabe
National Institute for Materials Science (NIMS)
Janina Maultzsch
University of Erlangen-Nuremberg (FAU)
Alexey Chernikov
Technische Universität Dresden
University of Regensburg
Ermin Malic
Philipps University Marburg
Chalmers, Physics, Condensed Matter and Materials Theory
2D-Tech
Physical Review B
2469-9950 (ISSN) 2469-9969 (eISSN)
Vol. 104 24 L2414062D material-based technology for industrial applications (2D-TECH)
GKN Aerospace Sweden (2D-tech), 2021-01-01 -- 2024-12-31.
VINNOVA (2019-00068), 2020-05-01 -- 2024-12-31.
Graphene Core Project 3 (Graphene Flagship)
European Commission (EC) (EC/H2020/881603), 2020-04-01 -- 2023-03-31.
Subject Categories
Atom and Molecular Physics and Optics
Other Physics Topics
Condensed Matter Physics
DOI
10.1103/PhysRevB.104.L241406