Nonclassical Exciton Diffusion in Monolayer WSe2
Artikel i vetenskaplig tidskrift, 2021
We experimentally demonstrate time-resolved exciton propagation in a monolayer semiconductor at cryogenic temperatures. Monitoring phonon-assisted recombination of dark states, we find a highly unusual case of exciton diffusion. While at 5 K the diffusivity is intrinsically limited by acoustic phonon scattering, we observe a pronounced decrease of the diffusion coefficient with increasing temperature, far below the activation threshold of higher-energy phonon modes. This behavior corresponds neither to well-known regimes of semiclassical free-particle transport nor to the thermally activated hopping in systems with strong localization. Its origin is discussed in the framework of both microscopic numerical and semiphenomenological analytical models illustrating the observed characteristics of nonclassical propagation. Challenging the established description of mobile excitons in monolayer semiconductors, these results open up avenues to study quantum transport phenomena for excitonic quasiparticles in atomically thin van der Waals materials and their heterostructures.
Författare
Koloman Wagner
Universität Regensburg
Jonas Zipfel
Lawrence Berkeley National Laboratory
Universität Regensburg
Roberto Rosati
Philipps-Universität Marburg
Edith Wietek
Universität Regensburg
Jonas D. Ziegler
Universität Regensburg
Samuel Brem
Philipps-Universität Marburg
Raul Perea Causin
2D-Tech
Chalmers, Fysik, Kondenserad materie- och materialteori
Takashi Taniguchi
National Institute for Materials Science (NIMS)
Kenji Watanabe
National Institute for Materials Science (NIMS)
Mikhail M. Glazov
Russian Academy of Sciences
Ermin Malic
2D-Tech
Chalmers, Fysik, Kondenserad materie- och materialteori
Alexey Chernikov
Universität Regensburg
Technische Universität Dresden
Physical Review Letters
0031-9007 (ISSN) 1079-7114 (eISSN)
Vol. 127 7 0768012D material-baserad teknologi för industriella applikationer (2D-TECH)
VINNOVA (2019-00068), 2020-05-01 -- 2024-12-31.
GKN Aerospace Sweden (2D-tech), 2021-01-01 -- 2024-12-31.
Graphene Core Project 3 (Graphene Flagship)
Europeiska kommissionen (EU) (EC/H2020/881603), 2020-04-01 -- 2023-03-31.
Ämneskategorier
Atom- och molekylfysik och optik
Annan fysik
Den kondenserade materiens fysik
DOI
10.1103/PhysRevLett.127.076801