Influence of the anharmonicity and phase transitions on the Fröhlich electron-phonon coupling of CsPbBr3: A first-principles study

Zeli Xu^a, Simon Thébaud^a, Marios Zacharias^c, Laurent Pedesseau^a, Claudine Katan^b, Jacky Even^a

^aUniv Rennes, INSA Rennes, CNRS, Institut FOTON-UMR 6082 F-35000, Rennes, France

^bUniv Rennes, ENSCR, INSA Rennes, CNRS, ISCR (Institut des Science Chimiques de Rennes), UMR 6226, 35700 Rennes, France

^cComputation-based Science and Technology Research Center, The Cyprus Institute, Aglantzia 2121, Nicosia, Cyprus

Proceedings of MATSUS Spring 2026 Conference (MATSUSSpring26)

H2 Halide perovskites for quantum technologies

Barcelona, Spain, 2026 March 23rd - 27th

Organizers: Quinten Akkerman, Simon Boehme and Maksym Kovalenko

Oral, Zeli Xu, presentation 248
Publication date: 15th December 2025

In recent years, 3D inorganic CsPbX3 (X=Cl, Br, I) perovskite materials have gained popularity for various optoelectronic applications. Particularly as quantum dots, these materials provide an attractive platform for classical and quantum light emission because of the high photoluminescence quantum yield, high optical coherence times, tunable emission wavelength and high photoluminescence stability [1,2]. For instance, quantum optics [3,4] and quantum computing [5] are their most promising applications.

However, their lattice vibrations and electron-phonon interactions remain incompletely understood due to strong anharmonicity and phase transitions. These effects can influence basic properties, including carrier mobility and excitonic effects. Therefore, investigating lattice vibrations and electron-phonon interactions in these materials are crucial. Here we present a first-principles study of CsPbBr3 across its orthorhombic, tetragonal, and cubic phases. We analyze the impact of the structural distortions on the phonon dispersions including additional effects related to local disorder and anharmonicity. We quantify the Fröhlich electron-phonon coupling strength for individual polar phonons. Moreover, we trace their symmetry evolution using group theory and standard band unfolding approaches. Despite pronounced structural transformations and enhanced anharmonicity at elevated temperatures, the long-range polar coupling mechanism associated with the LO mode lying at high frequency remains dominant throughout the three phases. In particular, the polar phonons at the orthorhombic Γ point are, overall, governed by the Γ point contributions from the cubic phase.

In conclusion, our study establishes a microscopic foundation for understanding polaronic and excitonic effects in CsPbBr3 and related nanostructures.

References:

[1] Protesescu, L.; Yakunin, S.; Bodnarchuk, M. I.; Krieg, F.; Caputo, R.; Hendon, C. H.; Yang, R. X.; Walsh, A.; Kovalenko, M. V. Nanocrystals of Cesium Lead Halide Perovskites (CsPbX3, X= Cl, Br, and I): Novel Optoelectronic Materials Showing Bright Emission with Wide Color Gamut. Nano Lett. 2015, 15 (6), 3692–3696.

[2] Tamarat, P.; Prin, E.; Berezovska, Y.; Moskalenko, A.; Nguyen, T. P. T.; Xia, C.; Hou, L.; Trebbia, J.-B.; Zacharias, M.; Pedesseau, L.; Katan, C.; Bodnarchuk, M. I.; Kovalenko, M. V.; Even, J.; Lounis, B. Universal Scaling Laws for Charge-Carrier Interactions with Quantum Confinement in Lead-Halide Perovskites. Nat. Commun. 2023, 14 (1), 229.

[3] Zhang, H.; Pasha, A.; Metcalf, I.; Zhou, J.; Staunstrup, M.; Zhu, Y.; Liao, S.; Ssennyimba, K.; Chen, J.-S.; Reddy, S. P.; Thébaud, S.; Hou, J.; Shuai, X.; Mandani, F.; Sidhik, S.; Jones, M. R.; Ma, X.; Balakrishna, R. G.; Susarla, S.; Ginger, D. S.; Katan, C.; Kanatzidis, M. G.; Bawendi, M. G.; Natelson, D.; Tamarat, P.; Lounis, B.; Even, J.; Mohite, A. D. Overcoming the Surface Paradox: Buried Perovskite Quantum Dots in Wide-Bandgap Perovskite Thin Films. arXiv:2501.06061 2025.

[4] Boehme, S. C.; Nguyen, T. P.; Zhu, C.; Cherniukh, I.; Feld, L. G.; Dirin, D. N.; Bodnarchuk, M. I.; Katan, C.; Even, J.; Kovalenko, M. V. Single-Photon Superabsorption in CsPbBr3 Perovskite Quantum Dots. Nat. Photonics 2025, 19, 864.

[5] Shields, A. J. Semiconductor Quantum Light Sources. Nat. Photonics 2007, 1 (4), 215–223.

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