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
photoluminescence
exciton-phonon interaction
transition-metal dichalcogenides
dark excitons
phonon side bands
Author
Samuel Brem
Chalmers, Physics, Condensed Matter and Materials Theory
August Ekman
Student at Chalmers
Dominik Christiansen
Technische Universität Berlin
Florian Katsch
Technische Universität Berlin
M. Selig
Technische Universität Berlin
Cedric Robert
Paul Sabatier University
Xavier Marie
Paul Sabatier University
Bernhard Urbaszek
Paul Sabatier University
A. Knorr
Technische Universität Berlin
Ermin Malic
2D-Tech
Chalmers, Physics, Condensed Matter and Materials Theory
Nano Letters
1530-6984 (ISSN) 1530-6992 (eISSN)
Vol. 20 4 2849-2856Exciton dynamics in atomically thin materials
Swedish Research Council (VR) (2018-00734), 2019-01-01 -- 2024-12-31.
Subject Categories (SSIF 2011)
Condensed Matter Physics
DOI
10.1021/acs.nanolett.0c00633
PubMed
32084315