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Mahan excitons in room-temperature methylammonium lead bromide perovskites

In a seminal paper, Mahan predicted that excitonic bound states can still exist in a semiconductor at electron-hole densities above the insulator-to-metal Mott transition. However, no clear evidence for this exotic quasiparticle, dubbed Mahan exciton, exists to date at room temperature. In this work...

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Autores principales: Palmieri, Tania, Baldini, Edoardo, Steinhoff, Alexander, Akrap, Ana, Kollár, Márton, Horváth, Endre, Forró, László, Jahnke, Frank, Chergui, Majed
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7016123/
https://www.ncbi.nlm.nih.gov/pubmed/32051405
http://dx.doi.org/10.1038/s41467-020-14683-5
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author Palmieri, Tania
Baldini, Edoardo
Steinhoff, Alexander
Akrap, Ana
Kollár, Márton
Horváth, Endre
Forró, László
Jahnke, Frank
Chergui, Majed
author_facet Palmieri, Tania
Baldini, Edoardo
Steinhoff, Alexander
Akrap, Ana
Kollár, Márton
Horváth, Endre
Forró, László
Jahnke, Frank
Chergui, Majed
author_sort Palmieri, Tania
collection PubMed
description In a seminal paper, Mahan predicted that excitonic bound states can still exist in a semiconductor at electron-hole densities above the insulator-to-metal Mott transition. However, no clear evidence for this exotic quasiparticle, dubbed Mahan exciton, exists to date at room temperature. In this work, we combine ultrafast broadband optical spectroscopy and advanced many-body calculations to reveal that organic-inorganic lead-bromide perovskites host Mahan excitons at room temperature. Persistence of the Wannier exciton peak and the enhancement of the above-bandgap absorption are observed at all achievable photoexcitation densities, well above the Mott density. This is supported by the solution of the semiconductor Bloch equations, which confirms that no sharp transition between the insulating and conductive phase occurs. Our results demonstrate the robustness of the bound states in a regime where exciton dissociation is otherwise expected, and offer promising perspectives in fundamental physics and in room-temperature applications involving high densities of charge carriers.
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spelling pubmed-70161232020-02-20 Mahan excitons in room-temperature methylammonium lead bromide perovskites Palmieri, Tania Baldini, Edoardo Steinhoff, Alexander Akrap, Ana Kollár, Márton Horváth, Endre Forró, László Jahnke, Frank Chergui, Majed Nat Commun Article In a seminal paper, Mahan predicted that excitonic bound states can still exist in a semiconductor at electron-hole densities above the insulator-to-metal Mott transition. However, no clear evidence for this exotic quasiparticle, dubbed Mahan exciton, exists to date at room temperature. In this work, we combine ultrafast broadband optical spectroscopy and advanced many-body calculations to reveal that organic-inorganic lead-bromide perovskites host Mahan excitons at room temperature. Persistence of the Wannier exciton peak and the enhancement of the above-bandgap absorption are observed at all achievable photoexcitation densities, well above the Mott density. This is supported by the solution of the semiconductor Bloch equations, which confirms that no sharp transition between the insulating and conductive phase occurs. Our results demonstrate the robustness of the bound states in a regime where exciton dissociation is otherwise expected, and offer promising perspectives in fundamental physics and in room-temperature applications involving high densities of charge carriers. Nature Publishing Group UK 2020-02-12 /pmc/articles/PMC7016123/ /pubmed/32051405 http://dx.doi.org/10.1038/s41467-020-14683-5 Text en © The Author(s) 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Palmieri, Tania
Baldini, Edoardo
Steinhoff, Alexander
Akrap, Ana
Kollár, Márton
Horváth, Endre
Forró, László
Jahnke, Frank
Chergui, Majed
Mahan excitons in room-temperature methylammonium lead bromide perovskites
title Mahan excitons in room-temperature methylammonium lead bromide perovskites
title_full Mahan excitons in room-temperature methylammonium lead bromide perovskites
title_fullStr Mahan excitons in room-temperature methylammonium lead bromide perovskites
title_full_unstemmed Mahan excitons in room-temperature methylammonium lead bromide perovskites
title_short Mahan excitons in room-temperature methylammonium lead bromide perovskites
title_sort mahan excitons in room-temperature methylammonium lead bromide perovskites
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7016123/
https://www.ncbi.nlm.nih.gov/pubmed/32051405
http://dx.doi.org/10.1038/s41467-020-14683-5
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