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arXiv · 2608.12765

A Unified Description of Electron-Phonon Coupling and Ion Migration in Metal Halide Perovskites

Bo Cai·Yan Yang·Yoshiki Sugai·Maddison Wiles·Dongxu He·Yang Yang·Junmin Xia·Shufen Chen·Carla Verdi·Siyu Chen·Nan Zhang·Ming-Gang Ju·Chao Liang·Julian A. Steele
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Abstract

The remarkable optoelectronic properties of metal halide perovskites are closely linked to their unusually soft and polar chemical bonds that enable both strong electron-phonon interactions and ion migration. Yet these two defining characteristics have largely been treated as independent consequences of the same underlying chemical bonding. Here we show that they originate from a common electronic-structure framework by developing a general description linking lattice dynamics, electron-phonon coupling, and halide ion migration across representative Pb-based, Sn-based, and double perovskites. Spectrally resolved phonon-mode contributions demonstrate that the low-frequency shearing modes dominate halide migration, whereas high-frequency stretching modes govern carrier scattering through the Fröhlich interaction in all three compositions. We introduce an orbital hybridization descriptor to unify these findings, which connects metal-halide bonding characteristics with the migration barrier energies and Fröhlich coupling strengths, indicating a cooperative evolution of these two properties. These findings provide a generalized microscopic mechanism for simultaneously optimizing charge and ionic transport in soft semiconductors.

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Bo Cai, Yan Yang, Yoshiki Sugai, Maddison Wiles, Dongxu He, Yang Yang, Junmin Xia, Shufen Chen, Carla Verdi, Siyu Chen, Nan Zhang, Ming-Gang Ju, Chao Liang, Julian A. Steele. 2026-08-13. A Unified Description of Electron-Phonon Coupling and Ion Migration in Metal Halide Perovskites. https://arxiv.org/abs/2608.12765

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