Flat dispersion at large momentum transfer at the onset of exciton polariton formation
Abstract Excitons are quasiparticles, comprised of an electron excited from the valence band and attracted to the hole left behind, that govern transport properties in transition metal dichalcogenides. Excitonic coherence specifically needs to be understood to realise applications based on Bose-Eins...
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2024-11-01
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| Series: | Communications Physics |
| Online Access: | https://doi.org/10.1038/s42005-024-01876-3 |
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| _version_ | 1850216514634907648 |
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| author | Hannah C. Nerl Khairi Elyas Zdravko Kochovski Nahid Talebi Christoph T. Koch Katja Höflich |
| author_facet | Hannah C. Nerl Khairi Elyas Zdravko Kochovski Nahid Talebi Christoph T. Koch Katja Höflich |
| author_sort | Hannah C. Nerl |
| collection | DOAJ |
| description | Abstract Excitons are quasiparticles, comprised of an electron excited from the valence band and attracted to the hole left behind, that govern transport properties in transition metal dichalcogenides. Excitonic coherence specifically needs to be understood to realise applications based on Bose-Einstein condensation and superfluidity. Here we used momentum-resolved electron energy-loss spectroscopy to obtain the complete energy-momentum dispersion of excitons in thin film and monolayer WSe 2 across the entire Brillouin zone, including outside of the light cone and for a large energy-loss range (1.5–4 eV). The measured dispersion of the modes was found to be flat. This suggests that the excitations are at the onset of polaritonic mode formation, propagating in the confinement of nanometer thin and monolayer WSe 2 . In combination with helium ion microscopy nanopatterning it was possible to probe and control these excitonic modes in thin film WSe 2 by modifying the local geometry through nanosized cuts. |
| format | Article |
| id | doaj-art-092687e8832a4cd5be8cf4fb09281cda |
| institution | OA Journals |
| issn | 2399-3650 |
| language | English |
| publishDate | 2024-11-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Communications Physics |
| spelling | doaj-art-092687e8832a4cd5be8cf4fb09281cda2025-08-20T02:08:16ZengNature PortfolioCommunications Physics2399-36502024-11-01711910.1038/s42005-024-01876-3Flat dispersion at large momentum transfer at the onset of exciton polariton formationHannah C. Nerl0Khairi Elyas1Zdravko Kochovski2Nahid Talebi3Christoph T. Koch4Katja Höflich5Department of Physics, Humboldt-Universität zu BerlinDepartment of Physics, Humboldt-Universität zu BerlinInstitute for Electrochemical Energy Storage, Helmholtz-Zentrum BerlinDepartment of Physics, Christian-Albrechts-Universität zu KielDepartment of Physics, Humboldt-Universität zu BerlinDepartment of Physics, Humboldt-Universität zu BerlinAbstract Excitons are quasiparticles, comprised of an electron excited from the valence band and attracted to the hole left behind, that govern transport properties in transition metal dichalcogenides. Excitonic coherence specifically needs to be understood to realise applications based on Bose-Einstein condensation and superfluidity. Here we used momentum-resolved electron energy-loss spectroscopy to obtain the complete energy-momentum dispersion of excitons in thin film and monolayer WSe 2 across the entire Brillouin zone, including outside of the light cone and for a large energy-loss range (1.5–4 eV). The measured dispersion of the modes was found to be flat. This suggests that the excitations are at the onset of polaritonic mode formation, propagating in the confinement of nanometer thin and monolayer WSe 2 . In combination with helium ion microscopy nanopatterning it was possible to probe and control these excitonic modes in thin film WSe 2 by modifying the local geometry through nanosized cuts.https://doi.org/10.1038/s42005-024-01876-3 |
| spellingShingle | Hannah C. Nerl Khairi Elyas Zdravko Kochovski Nahid Talebi Christoph T. Koch Katja Höflich Flat dispersion at large momentum transfer at the onset of exciton polariton formation Communications Physics |
| title | Flat dispersion at large momentum transfer at the onset of exciton polariton formation |
| title_full | Flat dispersion at large momentum transfer at the onset of exciton polariton formation |
| title_fullStr | Flat dispersion at large momentum transfer at the onset of exciton polariton formation |
| title_full_unstemmed | Flat dispersion at large momentum transfer at the onset of exciton polariton formation |
| title_short | Flat dispersion at large momentum transfer at the onset of exciton polariton formation |
| title_sort | flat dispersion at large momentum transfer at the onset of exciton polariton formation |
| url | https://doi.org/10.1038/s42005-024-01876-3 |
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