High-temperature observation of intralayer, interlayer, and Rydberg excitons in bulk van der Waals alloy single crystals

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Auteurs principaux: Taank, Pravrati, Ali, Asif, Raji, Aravind, Poonia, Ajay K., Beard, Matthew C., Singh, Ravi Shankar, Adarsh, K. V.
Format: Preprint
Publié: 2024
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author Taank, Pravrati
Ali, Asif
Raji, Aravind
Poonia, Ajay K.
Beard, Matthew C.
Singh, Ravi Shankar
Adarsh, K. V.
author_facet Taank, Pravrati
Ali, Asif
Raji, Aravind
Poonia, Ajay K.
Beard, Matthew C.
Singh, Ravi Shankar
Adarsh, K. V.
contents Transition metal dichalcogenides (TMDs) exhibit remarkable optical properties due to the diverse number of strongly bound excitons, which can be fine-tuned by alloying. Despite a flurry of research activity in characterizing these excitons, a comprehensive and profound understanding of their behavior with temperature is lacking. Here, we report the rich spectrum of excitonic features within bulk van der Waals alloy Mo$_{0.5}$W$_{0.5}$S$_2$ and Mo$_{0.5}$W$_{0.5}$Se$_2$ single crystals through temperature-dependent reflectance spectroscopy and first-principle calculations. We observed Rydberg excitons and interlayer excitons in both the single crystals. Notably, we provide the first experimental evidence of highly energetic A$^\prime$ and B$^\prime$ excitons in Mo$_{0.5}$W$_{0.5}$S$_2$ at room temperature. The strong carrier-phonon scattering significantly broadens the A$^\prime$, B$^\prime$ and interlayer excitons at room temperature in bulk Mo$_{0.5}$W$_{0.5}$S$_2$ single crystal compared to its selenide. Our findings, supported by density functional theory and Bethe-Salpeter equation calculations, signify the crucial role of carrier-phonon interactions. These results open pathways for next-generation optoelectronic devices and quantum technologies operating at high temperature.
format Preprint
id arxiv_https___arxiv_org_abs_2408_16306
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle High-temperature observation of intralayer, interlayer, and Rydberg excitons in bulk van der Waals alloy single crystals
Taank, Pravrati
Ali, Asif
Raji, Aravind
Poonia, Ajay K.
Beard, Matthew C.
Singh, Ravi Shankar
Adarsh, K. V.
Materials Science
Strongly Correlated Electrons
Transition metal dichalcogenides (TMDs) exhibit remarkable optical properties due to the diverse number of strongly bound excitons, which can be fine-tuned by alloying. Despite a flurry of research activity in characterizing these excitons, a comprehensive and profound understanding of their behavior with temperature is lacking. Here, we report the rich spectrum of excitonic features within bulk van der Waals alloy Mo$_{0.5}$W$_{0.5}$S$_2$ and Mo$_{0.5}$W$_{0.5}$Se$_2$ single crystals through temperature-dependent reflectance spectroscopy and first-principle calculations. We observed Rydberg excitons and interlayer excitons in both the single crystals. Notably, we provide the first experimental evidence of highly energetic A$^\prime$ and B$^\prime$ excitons in Mo$_{0.5}$W$_{0.5}$S$_2$ at room temperature. The strong carrier-phonon scattering significantly broadens the A$^\prime$, B$^\prime$ and interlayer excitons at room temperature in bulk Mo$_{0.5}$W$_{0.5}$S$_2$ single crystal compared to its selenide. Our findings, supported by density functional theory and Bethe-Salpeter equation calculations, signify the crucial role of carrier-phonon interactions. These results open pathways for next-generation optoelectronic devices and quantum technologies operating at high temperature.
title High-temperature observation of intralayer, interlayer, and Rydberg excitons in bulk van der Waals alloy single crystals
topic Materials Science
Strongly Correlated Electrons
url https://arxiv.org/abs/2408.16306