Ultrafast Dynamics of Valley-Polarized Excitons in WSe<sub>2</sub> Monolayer Studied by Few-Cycle Laser Pulses
We report on the experimental investigation of the ultrafast dynamics of valley-polarized excitons in monolayer WSe<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>2</m...
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MDPI AG
2023-03-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/13/7/1207 |
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| author | Petr Koutenský Artur Slobodeniuk Miroslav Bartoš František Trojánek Petr Malý Martin Kozák |
| author_facet | Petr Koutenský Artur Slobodeniuk Miroslav Bartoš František Trojánek Petr Malý Martin Kozák |
| author_sort | Petr Koutenský |
| collection | DOAJ |
| description | We report on the experimental investigation of the ultrafast dynamics of valley-polarized excitons in monolayer WSe<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>2</mn></msub></semantics></math></inline-formula> using transient reflection spectroscopy with few-cycle laser pulses with 7 fs duration. We observe that at room temperature, the anisotropic valley population of excitons decays on two different timescales. The shorter decay time of approximately 120 fs is related to the initial hot exciton relaxation related to the fast direct recombination of excitons from the radiative zone, while the slower picosecond dynamics corresponds to valley depolarization induced by Coloumb exchange-driven transitions of excitons between two inequivalent valleys. |
| first_indexed | 2024-03-11T05:28:23Z |
| format | Article |
| id | doaj.art-077fb8a2a3bb45eea7cdcd452c11433b |
| institution | Directory Open Access Journal |
| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-03-11T05:28:23Z |
| publishDate | 2023-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Nanomaterials |
| spelling | doaj.art-077fb8a2a3bb45eea7cdcd452c11433b2023-11-17T17:17:15ZengMDPI AGNanomaterials2079-49912023-03-01137120710.3390/nano13071207Ultrafast Dynamics of Valley-Polarized Excitons in WSe<sub>2</sub> Monolayer Studied by Few-Cycle Laser PulsesPetr Koutenský0Artur Slobodeniuk1Miroslav Bartoš2František Trojánek3Petr Malý4Martin Kozák5Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16 Prague, Czech RepublicDepartment of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague, Czech RepublicCentral European Institute of Technology, Brno University of Technology, Purkyňova 656/123, 612 00 Brno, Czech RepublicDepartment of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague, Czech RepublicDepartment of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague, Czech RepublicDepartment of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague, Czech RepublicWe report on the experimental investigation of the ultrafast dynamics of valley-polarized excitons in monolayer WSe<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>2</mn></msub></semantics></math></inline-formula> using transient reflection spectroscopy with few-cycle laser pulses with 7 fs duration. We observe that at room temperature, the anisotropic valley population of excitons decays on two different timescales. The shorter decay time of approximately 120 fs is related to the initial hot exciton relaxation related to the fast direct recombination of excitons from the radiative zone, while the slower picosecond dynamics corresponds to valley depolarization induced by Coloumb exchange-driven transitions of excitons between two inequivalent valleys.https://www.mdpi.com/2079-4991/13/7/1207transition metal dichalcogenide monolayersfemtosecond transient reflection spectroscopyintravalley excitons dynamics |
| spellingShingle | Petr Koutenský Artur Slobodeniuk Miroslav Bartoš František Trojánek Petr Malý Martin Kozák Ultrafast Dynamics of Valley-Polarized Excitons in WSe<sub>2</sub> Monolayer Studied by Few-Cycle Laser Pulses Nanomaterials transition metal dichalcogenide monolayers femtosecond transient reflection spectroscopy intravalley excitons dynamics |
| title | Ultrafast Dynamics of Valley-Polarized Excitons in WSe<sub>2</sub> Monolayer Studied by Few-Cycle Laser Pulses |
| title_full | Ultrafast Dynamics of Valley-Polarized Excitons in WSe<sub>2</sub> Monolayer Studied by Few-Cycle Laser Pulses |
| title_fullStr | Ultrafast Dynamics of Valley-Polarized Excitons in WSe<sub>2</sub> Monolayer Studied by Few-Cycle Laser Pulses |
| title_full_unstemmed | Ultrafast Dynamics of Valley-Polarized Excitons in WSe<sub>2</sub> Monolayer Studied by Few-Cycle Laser Pulses |
| title_short | Ultrafast Dynamics of Valley-Polarized Excitons in WSe<sub>2</sub> Monolayer Studied by Few-Cycle Laser Pulses |
| title_sort | ultrafast dynamics of valley polarized excitons in wse sub 2 sub monolayer studied by few cycle laser pulses |
| topic | transition metal dichalcogenide monolayers femtosecond transient reflection spectroscopy intravalley excitons dynamics |
| url | https://www.mdpi.com/2079-4991/13/7/1207 |
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