Magnetic field mixing and splitting of bright and dark excitons in monolayer MoSe2

Monolayers of semiconducting transition metal dichalcogenides (TMDCs) with unique spin-valley contrasting properties and remarkably strong excitonic effects continue to be a subject of intense research interests. These model 2D semiconductors feature two fundamental intravalley excitons species-opti...

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Bibliographic Details
Published in2d materials Vol. 7; no. 1
Main Authors Lu, Zhengguang, Rhodes, Daniel, Li, Zhipeng, Van Tuan, Dinh, Jiang, Yuxuan, Ludwig, Jonathan, Jiang, Zhigang, Lian, Zhen, Shi, Su-Fei, Hone, James, Dery, Hanan, Smirnov, Dmitry
Format Journal Article
LanguageEnglish
Published United States IOP Publishing 21.11.2019
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Summary:Monolayers of semiconducting transition metal dichalcogenides (TMDCs) with unique spin-valley contrasting properties and remarkably strong excitonic effects continue to be a subject of intense research interests. These model 2D semiconductors feature two fundamental intravalley excitons species-optically accessible 'bright' excitons with anti-parallel spins and optically inactive 'dark' excitons with parallel spins. For applications exploiting radiative recombination of bright excitons or long lifetime dark excitons, it is essential to understand the radiative character of the exciton ground state and establish the energy separation between the lowest energy bright and dark excitons. Here, we report a direct spectroscopic measure of dark excitons in monolayer MoSe2 encapsulated in hexagonal boron nitride. By applying strong in-plane magnetic field, we induce mixing and splitting of bright and dark exciton branches, which enables an accurate spectroscopic determination of their energies. We confirm the bright character of the exciton ground state separated by a 1.5 meV gap from the higher energy dark exciton state, much smaller compared to the previous theoretical expectations. These findings provide critical information for further improvement of the accurate theoretical description of TMDCs electronic structure.
Bibliography:2DM-104801
National Science Foundation (NSF)
USDOE Office of Science (SC), Basic Energy Sciences (BES)
US Air Force Office of Scientific Research (AFOSR)
FG02-07ER46451; DMR-1420634; 19YF1425200; FA9550-18-1-0312; DMR-1157490; DMR-1644779; SC0014349
ISSN:2053-1583
2053-1583
DOI:10.1088/2053-1583/ab5614