Exciton Relaxation Cascade in two-dimensional Transition Metal Dichalcogenides
Journal article, 2018

Monolayers of transition metal dichalcogenides (TMDs) are characterized by an extraordinarily strong Coulomb interaction giving rise to tightly bound excitons with binding energies of hundreds of meV. Excitons dominate the optical response as well as the ultrafast dynamics in TMDs. As a result, a microscopic understanding of exciton dynamics is the key for a technological application of these materials. In spite of this immense importance, elementary processes guiding the formation and relaxation of excitons after optical excitation of an electron-hole plasma has remained unexplored to a large extent. Here, we provide a fully quantum mechanical description of momentum- and energy-resolved exciton dynamics in monolayer molybdenum diselenide (MoSe2) including optical excitation, formation of excitons, radiative recombination as well as phonon-induced cascade-like relaxation down to the excitonic ground state. Based on the gained insights, we reveal experimentally measurable features in pump-probe spectra providing evidence for the exciton relaxation cascade.

Author

Samuel Brem

Chalmers, Physics, Condensed Matter Theory

Malte Selig

Technische Universität Berlin

Gunnar Berghäuser

Chalmers, Physics, Condensed Matter Theory

Ermin Malic

Chalmers, Physics, Condensed Matter Theory

Scientific Reports

2045-2322 (ISSN)

Vol. 8 8238

Graphene Core1. Graphene-based disruptive technologies (Graphene Flagship)

European Commission (Horizon 2020), 2016-04-01 -- 2018-03-31.

Subject Categories

Atom and Molecular Physics and Optics

Condensed Matter Physics

DOI

10.1038/s41598-018-25906-7

PubMed

29844321

More information

Latest update

9/5/2018 5