Giant Electron-Phonon Coupling Induced Band-Gap Renormalization in Anharmonic Silver Chalcohalide Antiperovskites
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| Main Authors: | , , , , , , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866913585207181312 |
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| author | Benítez, Pol Chen, Siyu Jiang, Ruoshi López, Cibrán Tamarit, Josep-Lluís Íñiguez-González, Jorge Saucedo, Edgardo Monserrat, Bartomeu Cazorla, Claudio |
| author_facet | Benítez, Pol Chen, Siyu Jiang, Ruoshi López, Cibrán Tamarit, Josep-Lluís Íñiguez-González, Jorge Saucedo, Edgardo Monserrat, Bartomeu Cazorla, Claudio |
| contents | Silver chalcohalide antiperovskites (CAP), Ag$_{3}$XY (X = S, Se; Y = Br, I), are a family of highly anharmonic inorganic compounds with great potential for energy applications. However, a substantial and unresolved discrepancy exists between the optoelectronic properties predicted by theoretical first-principles methods and those measured experimentally at room temperature, hindering the fundamental understanding and rational engineering of CAP. In this work, we employ density functional theory, tight-binding calculations, and anharmonic Fröhlich theory to investigate the optoelectronic properties of CAP at finite temperatures. Near room temperature, we observe a giant band-gap ($E_{g}$) reduction of approximately $20$-$60$\% relative to the value calculated at $T = 0$ K, bringing the estimated $E_{g}$ into excellent agreement with experimental measurements. This relative $T$-induced band-gap renormalization is roughly twice the largest value previously reported in the literature for similar temperature ranges. Low-energy optical polar phonon modes, which break inversion symmetry and promote the overlap between silver and chalcogen $s$ electronic orbitals in the conduction band, are identified as the primary contributors to this giant $E_{g}$ reduction. Furthermore, when considering temperature effects, the optical absorption coefficient of CAP increases by nearly an order of magnitude for visible light frequencies. These insights not only bridge a crucial gap between theory and experiment but also open pathways for future technologies where temperature, electric fields, or light dynamically tailor optoelectronic behavior, positioning CAP as a versatile platform for next-generation energy applications. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2411_16279 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Giant Electron-Phonon Coupling Induced Band-Gap Renormalization in Anharmonic Silver Chalcohalide Antiperovskites Benítez, Pol Chen, Siyu Jiang, Ruoshi López, Cibrán Tamarit, Josep-Lluís Íñiguez-González, Jorge Saucedo, Edgardo Monserrat, Bartomeu Cazorla, Claudio Materials Science Silver chalcohalide antiperovskites (CAP), Ag$_{3}$XY (X = S, Se; Y = Br, I), are a family of highly anharmonic inorganic compounds with great potential for energy applications. However, a substantial and unresolved discrepancy exists between the optoelectronic properties predicted by theoretical first-principles methods and those measured experimentally at room temperature, hindering the fundamental understanding and rational engineering of CAP. In this work, we employ density functional theory, tight-binding calculations, and anharmonic Fröhlich theory to investigate the optoelectronic properties of CAP at finite temperatures. Near room temperature, we observe a giant band-gap ($E_{g}$) reduction of approximately $20$-$60$\% relative to the value calculated at $T = 0$ K, bringing the estimated $E_{g}$ into excellent agreement with experimental measurements. This relative $T$-induced band-gap renormalization is roughly twice the largest value previously reported in the literature for similar temperature ranges. Low-energy optical polar phonon modes, which break inversion symmetry and promote the overlap between silver and chalcogen $s$ electronic orbitals in the conduction band, are identified as the primary contributors to this giant $E_{g}$ reduction. Furthermore, when considering temperature effects, the optical absorption coefficient of CAP increases by nearly an order of magnitude for visible light frequencies. These insights not only bridge a crucial gap between theory and experiment but also open pathways for future technologies where temperature, electric fields, or light dynamically tailor optoelectronic behavior, positioning CAP as a versatile platform for next-generation energy applications. |
| title | Giant Electron-Phonon Coupling Induced Band-Gap Renormalization in Anharmonic Silver Chalcohalide Antiperovskites |
| topic | Materials Science |
| url | https://arxiv.org/abs/2411.16279 |