Reference : Interlayer and intralayer excitons in MoS2/WS2 and MoSe2/WSe2 heterobilayers
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Physics
Physics and Materials Science
http://hdl.handle.net/10993/38247
Interlayer and intralayer excitons in MoS2/WS2 and MoSe2/WSe2 heterobilayers
English
Torun, Engin mailto [University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit >]
Miranda, Henrique P.C. [Universitè Catholique de Louvain, Belgium > Institute of Condensed Matter and Nanosciences (IMCN/NAPS) > > ; University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit]
Molina-Sánchez, Alejandro [University of Valencia, Spain > Institute of Materials Science (ICMUV)]
Wirtz, Ludger mailto [University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit >]
Jun-2018
Physical Review. B, Condensed Matter
American Physical Society
97
245427
Yes
International
0163-1829
1095-3795
New York
MD
[en] 2D heterolayers ; Excitons ; ab-initio many body perturbation theory
[en] Accurately described excitonic properties of transition metal dichalcogenide heterobilayers (HBLs) are crucial to comprehend the optical response and the charge carrier dynamics of them. Excitons in multilayer systems possess an inter- or intralayer character whose spectral positions depend on their binding energy and the band alignment of the constituent single layers. In this paper, we report the electronic structure and the absorption spectra of MoS2/WS2 and MoSe2/WSe2 HBLs from first-principles calculations. We explore the spectral positions, binding energies, and the origins of inter- and intralayer excitons and compare our results with experimental observations. The absorption spectra of the systems are obtained by solving the Bethe-Salpeter equation on top of a G0W0 calculation, which corrects the independent-particle eigenvalues obtained from density-functional theory. Our calculations reveal that the lowest energy exciton in both HBLs possess an interlayer character which is decisive regarding their possible device applications. Due to the spatially separated nature of the charge carriers, the binding energy of interlayer excitons might be expected to be considerably smaller than that of intralayer ones. However, according to our calculations, the binding energy of lowest energy interlayer excitons is only ∼20% lower due to the weaker screening of the Coulomb interaction between layers of the HBLs. Therefore, it can be deduced that the spectral positions of the interlayer excitons with respect to intralayer ones are mostly determined by the band offset of the constituent single layers. By comparing oscillator strengths and thermal occupation factors, we show that in luminescence at low temperature, the interlayer exciton peak becomes dominant, while in absorption it is almost invisible.
University of Luxembourg: High Performance Computing - ULHPC
Fonds National de la Recherche - FnR
Researchers ; Professionals ; Students
http://hdl.handle.net/10993/38247
10.1103/PhysRevB.97.245427
FnR ; FNR7490149 > Ludger Wirtz > NANOTMD > 20 Electric transport and superconductivity in TransitionMetal Dichalcogenides nanolayers > 01/02/2014 > 31/01/2019 > 2013; FNR7731521 > Alejandro Molina-Sánchez > FAST-2DMAT > Modelling of carrier dynamics and ultra-fast spectroscopy in two-dimensional materials > 01/12/2014 > 31/03/2017 > 2014

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