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Flat-Band-Induced Many-Body Interactions and Exciton Complexes in a Layered Semiconductor

[Image: see text] Interactions among a collection of particles generate many-body effects in solids that result in striking modifications of material properties. The heavy carrier mass that yields strong interactions and gate control of carrier density over a wide range makes two-dimensional semicon...

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Detalles Bibliográficos
Autores principales: Pasquale, Gabriele, Sun, Zhe, Čerņevičs, Kristia̅ns, Perea-Causin, Raul, Tagarelli, Fedele, Watanabe, Kenji, Taniguchi, Takashi, Malic, Ermin, Yazyev, Oleg V., Kis, Andras
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2022
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9707521/
https://www.ncbi.nlm.nih.gov/pubmed/36346874
http://dx.doi.org/10.1021/acs.nanolett.2c02965
Descripción
Sumario:[Image: see text] Interactions among a collection of particles generate many-body effects in solids that result in striking modifications of material properties. The heavy carrier mass that yields strong interactions and gate control of carrier density over a wide range makes two-dimensional semiconductors an exciting playground to explore many-body physics. The family of III–VI metal monochalcogenides emerges as a new platform for this purpose because of its excellent optical properties and the flat valence band dispersion. In this work, we present a complete study of charge-tunable excitons in few-layer InSe by photoluminescence spectroscopy. From the optical spectra, we establish that free excitons in InSe are more likely to be captured by ionized donors leading to the formation of bound exciton complexes. Surprisingly, a pronounced red shift of the exciton energy accompanied by a decrease of the exciton binding energy upon hole-doping reveals a significant band gap renormalization induced by the presence of the Fermi reservoir.