Valley-optical absorption in planar transition metal dichalcogenide superlattices
In this study, we investigate the optical absorption of a planar superlattice comprising alternatively arranged two-dimensional Transition Metal DiChalcogenide semiconductors. Within a semi-classical model and using the Dirac-like equation in the presence of light interaction as a perturbation, we o...
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sg-ntu-dr.10356-1694262023-07-21T15:45:55Z Valley-optical absorption in planar transition metal dichalcogenide superlattices Hashemi, R. Shojaei, S. Rezaei, B. Liu, Zheng School of Materials Science and Engineering Engineering::Materials Monolayer Van Der Waals In this study, we investigate the optical absorption of a planar superlattice comprising alternatively arranged two-dimensional Transition Metal DiChalcogenide semiconductors. Within a semi-classical model and using the Dirac-like equation in the presence of light interaction as a perturbation, we obtained the governing Hamiltonian. Using this Hamiltonian, we derived a fully analytical relationship for the absorption coefficient of the structure. By calculating the effective mass for different bands and using the Drude-Lorentz model, our approach is able to determine the oscillator strength and the effective refractive index of the structure. We found that the spin-orbit coupling has important effect on the absorption coefficient and energy bands where it reduces the absorption coefficient of the structure from typical value of [Formula: see text]-[Formula: see text], also the valence band experiences a significant blue shift, while the conduction band shows minor changes due to spin orbit coupling. Moreover, the role of incident light angle and light polarization were studied in details at different valleys of [Formula: see text] and [Formula: see text]. The most important finding is that by changing the polarization of incident light, it is possible to increase the absorption coefficients of [Formula: see text] and [Formula: see text] valleys by up to 30 times. For light propagation direction close to perpendicular to the plane of the superlattice, the right-circular polarization is absorbed only by [Formula: see text] valley in contrast to the left-circular polarization, which is absorbed by the [Formula: see text] valley. Our model might be used to design newly developed 2D optovalleytronic devices. Published version 2023-07-18T05:33:39Z 2023-07-18T05:33:39Z 2023 Journal Article Hashemi, R., Shojaei, S., Rezaei, B. & Liu, Z. (2023). Valley-optical absorption in planar transition metal dichalcogenide superlattices. Scientific Reports, 13(1), 5439-. https://dx.doi.org/10.1038/s41598-023-31950-9 2045-2322 https://hdl.handle.net/10356/169426 10.1038/s41598-023-31950-9 37012309 2-s2.0-85151454675 1 13 5439 en Scientific Reports © 2023 The Author(s). This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. application/pdf |
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Engineering::Materials Monolayer Van Der Waals Hashemi, R. Shojaei, S. Rezaei, B. Liu, Zheng Valley-optical absorption in planar transition metal dichalcogenide superlattices |
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In this study, we investigate the optical absorption of a planar superlattice comprising alternatively arranged two-dimensional Transition Metal DiChalcogenide semiconductors. Within a semi-classical model and using the Dirac-like equation in the presence of light interaction as a perturbation, we obtained the governing Hamiltonian. Using this Hamiltonian, we derived a fully analytical relationship for the absorption coefficient of the structure. By calculating the effective mass for different bands and using the Drude-Lorentz model, our approach is able to determine the oscillator strength and the effective refractive index of the structure. We found that the spin-orbit coupling has important effect on the absorption coefficient and energy bands where it reduces the absorption coefficient of the structure from typical value of [Formula: see text]-[Formula: see text], also the valence band experiences a significant blue shift, while the conduction band shows minor changes due to spin orbit coupling. Moreover, the role of incident light angle and light polarization were studied in details at different valleys of [Formula: see text] and [Formula: see text]. The most important finding is that by changing the polarization of incident light, it is possible to increase the absorption coefficients of [Formula: see text] and [Formula: see text] valleys by up to 30 times. For light propagation direction close to perpendicular to the plane of the superlattice, the right-circular polarization is absorbed only by [Formula: see text] valley in contrast to the left-circular polarization, which is absorbed by the [Formula: see text] valley. Our model might be used to design newly developed 2D optovalleytronic devices. |
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School of Materials Science and Engineering |
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School of Materials Science and Engineering Hashemi, R. Shojaei, S. Rezaei, B. Liu, Zheng |
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Article |
author |
Hashemi, R. Shojaei, S. Rezaei, B. Liu, Zheng |
author_sort |
Hashemi, R. |
title |
Valley-optical absorption in planar transition metal dichalcogenide superlattices |
title_short |
Valley-optical absorption in planar transition metal dichalcogenide superlattices |
title_full |
Valley-optical absorption in planar transition metal dichalcogenide superlattices |
title_fullStr |
Valley-optical absorption in planar transition metal dichalcogenide superlattices |
title_full_unstemmed |
Valley-optical absorption in planar transition metal dichalcogenide superlattices |
title_sort |
valley-optical absorption in planar transition metal dichalcogenide superlattices |
publishDate |
2023 |
url |
https://hdl.handle.net/10356/169426 |
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1773551386596737024 |