Excitonic linewidth and coherence lifetime in monolayer transition metal dichalcogenides

Atomically thin transition metal dichalcogenides are direct-gap semiconductors with strong light–matter and Coulomb interactions. The latter accounts for tightly bound excitons, which dominate their optical properties. Besides the optically accessible bright excitons, these systems exhibit a variety...

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Main Authors:	Selig, Malte, Berghäuser, Gunnar, Raja, Archana, Nagler, Philipp, Schüller, Christian, Heinz, Tony F., Korn, Tobias, Chernikov, Alexey, Malic, Ermin, Knorr, Andreas
Format:	Online
Language:	English
Published:	Nature Publishing Group 2016
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5103057/

id	pubmed-5103057
recordtype	oai_dc
spelling	pubmed-51030572016-11-18 Excitonic linewidth and coherence lifetime in monolayer transition metal dichalcogenides Selig, Malte Berghäuser, Gunnar Raja, Archana Nagler, Philipp Schüller, Christian Heinz, Tony F. Korn, Tobias Chernikov, Alexey Malic, Ermin Knorr, Andreas Article Atomically thin transition metal dichalcogenides are direct-gap semiconductors with strong light–matter and Coulomb interactions. The latter accounts for tightly bound excitons, which dominate their optical properties. Besides the optically accessible bright excitons, these systems exhibit a variety of dark excitonic states. They are not visible in the optical spectra, but can strongly influence the coherence lifetime and the linewidth of the emission from bright exciton states. Here, we investigate the microscopic origin of the excitonic coherence lifetime in two representative materials (WS2 and MoSe2) through a study combining microscopic theory with spectroscopic measurements. We show that the excitonic coherence lifetime is determined by phonon-induced intravalley scattering and intervalley scattering into dark excitonic states. In particular, in WS2, we identify exciton relaxation processes involving phonon emission into lower-lying dark states that are operative at all temperatures. Nature Publishing Group 2016-11-07 /pmc/articles/PMC5103057/ /pubmed/27819288 http://dx.doi.org/10.1038/ncomms13279 Text en Copyright © 2016, The Author(s) http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Selig, Malte Berghäuser, Gunnar Raja, Archana Nagler, Philipp Schüller, Christian Heinz, Tony F. Korn, Tobias Chernikov, Alexey Malic, Ermin Knorr, Andreas
spellingShingle	Selig, Malte Berghäuser, Gunnar Raja, Archana Nagler, Philipp Schüller, Christian Heinz, Tony F. Korn, Tobias Chernikov, Alexey Malic, Ermin Knorr, Andreas Excitonic linewidth and coherence lifetime in monolayer transition metal dichalcogenides
author_facet	Selig, Malte Berghäuser, Gunnar Raja, Archana Nagler, Philipp Schüller, Christian Heinz, Tony F. Korn, Tobias Chernikov, Alexey Malic, Ermin Knorr, Andreas
author_sort	Selig, Malte
title	Excitonic linewidth and coherence lifetime in monolayer transition metal dichalcogenides
title_short	Excitonic linewidth and coherence lifetime in monolayer transition metal dichalcogenides
title_full	Excitonic linewidth and coherence lifetime in monolayer transition metal dichalcogenides
title_fullStr	Excitonic linewidth and coherence lifetime in monolayer transition metal dichalcogenides
title_full_unstemmed	Excitonic linewidth and coherence lifetime in monolayer transition metal dichalcogenides
title_sort	excitonic linewidth and coherence lifetime in monolayer transition metal dichalcogenides
description	Atomically thin transition metal dichalcogenides are direct-gap semiconductors with strong light–matter and Coulomb interactions. The latter accounts for tightly bound excitons, which dominate their optical properties. Besides the optically accessible bright excitons, these systems exhibit a variety of dark excitonic states. They are not visible in the optical spectra, but can strongly influence the coherence lifetime and the linewidth of the emission from bright exciton states. Here, we investigate the microscopic origin of the excitonic coherence lifetime in two representative materials (WS2 and MoSe2) through a study combining microscopic theory with spectroscopic measurements. We show that the excitonic coherence lifetime is determined by phonon-induced intravalley scattering and intervalley scattering into dark excitonic states. In particular, in WS2, we identify exciton relaxation processes involving phonon emission into lower-lying dark states that are operative at all temperatures.
publisher	Nature Publishing Group
publishDate	2016
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5103057/
_version_	1613720608228507648

Excitonic linewidth and coherence lifetime in monolayer transition metal dichalcogenides

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