Phonon-Assisted Photoluminescence from Indirect Excitons in Monolayers of Transition-Metal Dichalcogenides
Journal article, 2020

The photoluminescence (PL) spectrum of transition-metal dichalcogenides (TMDs) shows a multitude of emission peaks below the bright exciton line, and not all of them have been explained yet. Here, we study the emission traces of phonon-assisted recombinations of indirect excitons. To this end, we develop a microscopic theory describing simultaneous exciton, phonon, and photon interaction and including consistent many-particle dephasing. We explain the drastically different PL below the bright exciton in tungsten- and molybdenum-based materials as the result of different configurations of bright and momentum-dark states. In good agreement with experiments, our calculations predict that WSe2 exhibits clearly visible low-temperature PL signals stemming from the phonon-assisted recombination of momentum-dark K-K′ excitons.

microscopic model

transition-metal dichalcogenides

dark excitons

exciton-phonon interaction

photoluminescence

phonon side bands

Author

Samuel Brem

Chalmers, Physics, Condensed Matter and Materials Theory

August Ekman

Chalmers, Physics

Dominik Christiansen

Technische Universität Berlin

Florian Katsch

Technische Universität Berlin

M. Selig

Technische Universität Berlin

Cedric Robert

Universite Paul Sabatier Toulouse III

Xavier Marie

Universite Paul Sabatier Toulouse III

Bernhard Urbaszek

Universite Paul Sabatier Toulouse III

A. Knorr

Technische Universität Berlin

Ermin Malic

Chalmers, Physics, Condensed Matter and Materials Theory

2D-Tech

Nano Letters

1530-6984 (ISSN) 1530-6992 (eISSN)

Vol. 20 4 2849-2856

Exciton dynamics in atomically thin materials

Swedish Research Council (VR), 2019-01-01 -- 2024-12-31.

Subject Categories

Atom and Molecular Physics and Optics

Theoretical Chemistry

Condensed Matter Physics

DOI

10.1021/acs.nanolett.0c00633

PubMed

32084315

More information

Latest update

10/13/2020