Magnetic brightening of light-like excitons in a monolayer semiconductor
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arXiv
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| Auteurs principaux: | , , , , , , |
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| Format: | Preprint |
| Publié: |
2025
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| _version_ | 1866908494735605760 |
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| author | Delhomme, A. Amit, T. Ji, P. Faugeras, C. Refaely-Abramson, S. Finley, J. J. Stier, A. V. |
| author_facet | Delhomme, A. Amit, T. Ji, P. Faugeras, C. Refaely-Abramson, S. Finley, J. J. Stier, A. V. |
| contents | Monolayer transition-metal dichalcogenides, such as WSe$_2$, are direct gap, multi-valley semiconductors. Long-range electron-hole exchange interactions mix the valleys, yielding dispersion relations for massive ($\propto Q^2$) as well as light-like ($\propto Q$) excitons. We report magneto-photoluminescence spectroscopy of excitons in the monolayer semiconductor WSe$_2$ to $B = \pm25$T. The magnetic field-dependent line shape of the neutral exciton reveals the emergence of a new blue-detuned emission peak in both field orientations. Analyzing the distinct magnetic field-dependent shifts of both peaks facilitates the identification of the emergent feature as a spin-singlet with a significantly smaller reduced exciton mass as compared to the neutral exciton. The intensity of the emergent feature increases with magnetic field according to $\propto B^2$, as expected for a linear dispersion relation. The density-dependent diamagnetic shift ratios of both features follow the expected density dependence of the electron-hole exchange interactions. We interpret our observations within a picture of magnetic-field-induced coupling between the bright massive and quasi dark light-like exciton, leading to its brightening. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2508_13784 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Magnetic brightening of light-like excitons in a monolayer semiconductor Delhomme, A. Amit, T. Ji, P. Faugeras, C. Refaely-Abramson, S. Finley, J. J. Stier, A. V. Mesoscale and Nanoscale Physics Monolayer transition-metal dichalcogenides, such as WSe$_2$, are direct gap, multi-valley semiconductors. Long-range electron-hole exchange interactions mix the valleys, yielding dispersion relations for massive ($\propto Q^2$) as well as light-like ($\propto Q$) excitons. We report magneto-photoluminescence spectroscopy of excitons in the monolayer semiconductor WSe$_2$ to $B = \pm25$T. The magnetic field-dependent line shape of the neutral exciton reveals the emergence of a new blue-detuned emission peak in both field orientations. Analyzing the distinct magnetic field-dependent shifts of both peaks facilitates the identification of the emergent feature as a spin-singlet with a significantly smaller reduced exciton mass as compared to the neutral exciton. The intensity of the emergent feature increases with magnetic field according to $\propto B^2$, as expected for a linear dispersion relation. The density-dependent diamagnetic shift ratios of both features follow the expected density dependence of the electron-hole exchange interactions. We interpret our observations within a picture of magnetic-field-induced coupling between the bright massive and quasi dark light-like exciton, leading to its brightening. |
| title | Magnetic brightening of light-like excitons in a monolayer semiconductor |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2508.13784 |