Giant thermally induced band-gap renormalization in anharmonic silver chalcohalide antiperovskites.

Acknowledgements: We acknowledge financial support by MICIN/AEI/10.13039/501100011033 and ERDF/EU under the grants TED2021-130265B-C22, TED2021-130265B-C21, PID2023-146623NB-I00, PID2023-147469NB-C21 and RYC2018-024947-I and by the Generalitat de Catalunya under the grants 2021SGR-00343, 2021SGR-01519 and 2021SGR-01411. Computational support was provided by the Red Española de Supercomputación under the grants FI-2024-1-0005, FI-2024-2-0003 and FI-2024-3-0004. This work is part of the Maria de Maeztu Units of Excellence Programme CEX2023-001300-M funded by MCIN/AEI (10.13039/501100011033). P. B. acknowledges support from the predoctoral program AGAUR-FI ajuts (2024 FI-1 00070) Joan Oró, which is backed by the Secretariat of Universities and Research of the Department of Research and Universities of the Generalitat of Catalonia, as well as the European Social Plus Fund. C. L. acknowledges support from the Spanish Ministry of Science, Innovation and Universities under an FPU grant. E. S. and J.-Ll.T. are grateful to the ICREA Academia program. Work at LIST was supported by the Luxembourg National Research Fund through grant C21/MS/15799044/FERRODYNAMICS. This project received funding from the European Union's H2020 European Research Council under the grant agreement number 866018 (SENSATE). S. C. and B. M. are supported by a EPSRC grant [EP/V062654/1] and R. J. and B. M. are supported by a UKRI Future Leaders Fellowship [MR/V023926/1]. B. M. also acknowledges support from the Gianna Angelopoulos Programme for Science, Technology, and Innovation, and from the Winton Programme for the Physics of Sustainability.