Academic Journal
Multiple Lattice Instabilities and Complex Ground State in Cs_{2}AgBiBr_{6}
| العنوان: | Multiple Lattice Instabilities and Complex Ground State in Cs_{2}AgBiBr_{6} |
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| المؤلفون: | Xing He, Matthew Krogstad, Mayanak K. Gupta, Tyson Lanigan-Atkins, Chengjie Mao, Feng Ye, Yaohua Liu, Tao Hong, Songxue Chi, Haotong Wei, Jinsong Huang, Stephan Rosenkranz, Raymond Osborn, Olivier Delaire |
| المصدر: | PRX Energy, Vol 3, Iss 1, p 013014 (2024) |
| بيانات النشر: | American Physical Society, 2024. |
| سنة النشر: | 2024 |
| المجموعة: | LCC:Production of electric energy or power. Powerplants. Central stations LCC:Renewable energy sources |
| مصطلحات موضوعية: | Production of electric energy or power. Powerplants. Central stations, TK1001-1841, Renewable energy sources, TJ807-830 |
| الوصف: | Metal-halide perovskites (MHPs) are attracting considerable interest for optoelectronic applications, with Cs_{2}AgBiBr_{6} one of the main contenders among lead-free systems. Cs_{2}AgBiBr_{6} crystallizes in a nominally double-perovskite structure, but exhibits a soft lattice with large atomic fluctuations characteristic of MHPs. While crucial to understand electron-phonon and phonon-phonon couplings, the spatiotemporal correlations of these fluctuations remain largely unknown. Here, we reveal these correlations using comprehensive neutron and x-ray scattering measurements on Cs_{2}AgBiBr_{6} single crystals, complemented with first-principles simulations augmented with machine-learned neural-network potentials. We report the discovery of an unexpected complex modulated ground-state structure containing several hundred atoms, arising from a soft-phonon instability of the low-temperature tetragonal phase. Further, our experiments and simulations both reveal extensive correlated two-dimensional fluctuations of Br octahedra at finite temperature, arising from soft optic phonons that are strongly broadened by anhamonicity, reflecting very shallow potential wells. These results provide new insights into the atomic structure and fluctuations in MHPs, critical to understand and control their thermal and optoelectronic properties. |
| نوع الوثيقة: | article |
| وصف الملف: | electronic resource |
| اللغة: | English |
| تدمد: | 2768-5608 |
| Relation: | https://doaj.org/toc/2768-5608 |
| DOI: | 10.1103/PRXEnergy.3.013014 |
| URL الوصول: | https://doaj.org/article/ae938349bf6c4a3f86c0b683859c8ed2 |
| رقم الانضمام: | edsdoj.938349bf6c4a3f86c0b683859c8ed2 |
| قاعدة البيانات: | Directory of Open Access Journals |
Full Text Finder | تدمد: | 27685608 |
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| DOI: | 10.1103/PRXEnergy.3.013014 |