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

Universität Regensburg

Lawrence Berkeley National Laboratory

Roberto Rosati

Philipps-Universität Marburg

Edith Wietek

Universität Regensburg

Jonas D. Ziegler

Universität Regensburg

Samuel Brem

Philipps-Universität Marburg

Raul Perea Causin

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

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 076801

Graphene Core Project 3 (Graphene Flagship)

Europeiska kommissionen (EU) (881603GrapheneCore3), 2020-04-01 -- 2023-03-31.

Ämneskategorier

Atom- och molekylfysik och optik

Annan fysik

Den kondenserade materiens fysik

DOI

10.1103/PhysRevLett.127.076801

Mer information

Senast uppdaterat

2021-08-24