Valley-controlled many-body exciton interactions in monolayer WSe$_2$ phototransistors
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arXiv
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| Auteurs principaux: | , , , , , , , , |
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| Format: | Preprint |
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2026
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| _version_ | 1866916051767263232 |
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| author | Vaquero, Daniel Cordero-Silis, Cédric A. Erkensten, Daniel Rosati, Roberto Takens, Martijn H. Watanabe, Kenji Taniguchi, Takashi Malic, Ermin Guimarães, Marcos H. D. |
| author_facet | Vaquero, Daniel Cordero-Silis, Cédric A. Erkensten, Daniel Rosati, Roberto Takens, Martijn H. Watanabe, Kenji Taniguchi, Takashi Malic, Ermin Guimarães, Marcos H. D. |
| contents | Many-body exciton interactions shape the optoelectronic response of atomically-thin transition metal dichalcogenides, yet optical control of these interactions remains largely unexplored. To date, modulation of exciton-exciton interactions has primarily relied on electrical gating or van der Waals engineering. Here, we demonstrate all-optical control of many-body exciton interactions in monolayer WSe$_2$ via valley-selective excitation using polarization-resolved pulsed-laser photocurrent spectroscopy. Circular excitation selectively populates excitons in a single valley, whereas linear excitation populates both valleys, inducing a valley-dependent nonlinear photoresponse. We observe helicity-dependent exciton renormalization, alongside a two-fold enhancement of sublinear photocurrent scaling under circular excitation, reflecting single-valley population of interacting excitons. A microscopic model incorporating intervalley-exchange and exciton-exciton annihilation mediated by dark and bright exciton populations reproduces the nonlinear valley-selective response. These results establish the valley degree of freedom as an all-optical control parameter for tuning many-body excitonic effects and, exploring correlated exciton states and valleytronic applications in two-dimensional semiconductors. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2604_08382 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Valley-controlled many-body exciton interactions in monolayer WSe$_2$ phototransistors Vaquero, Daniel Cordero-Silis, Cédric A. Erkensten, Daniel Rosati, Roberto Takens, Martijn H. Watanabe, Kenji Taniguchi, Takashi Malic, Ermin Guimarães, Marcos H. D. Mesoscale and Nanoscale Physics Materials Science Optics Many-body exciton interactions shape the optoelectronic response of atomically-thin transition metal dichalcogenides, yet optical control of these interactions remains largely unexplored. To date, modulation of exciton-exciton interactions has primarily relied on electrical gating or van der Waals engineering. Here, we demonstrate all-optical control of many-body exciton interactions in monolayer WSe$_2$ via valley-selective excitation using polarization-resolved pulsed-laser photocurrent spectroscopy. Circular excitation selectively populates excitons in a single valley, whereas linear excitation populates both valleys, inducing a valley-dependent nonlinear photoresponse. We observe helicity-dependent exciton renormalization, alongside a two-fold enhancement of sublinear photocurrent scaling under circular excitation, reflecting single-valley population of interacting excitons. A microscopic model incorporating intervalley-exchange and exciton-exciton annihilation mediated by dark and bright exciton populations reproduces the nonlinear valley-selective response. These results establish the valley degree of freedom as an all-optical control parameter for tuning many-body excitonic effects and, exploring correlated exciton states and valleytronic applications in two-dimensional semiconductors. |
| title | Valley-controlled many-body exciton interactions in monolayer WSe$_2$ phototransistors |
| topic | Mesoscale and Nanoscale Physics Materials Science Optics |
| url | https://arxiv.org/abs/2604.08382 |