2025/06/11 by Zacharias, Marios, Volonakis, George, Pedesseau, Laurent +3 · 2 citations
#Disordered Systems and Neural Networks (cond-mat.dis-nn) #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci)
paper · doi:10.48550/arxiv.2506.09673
Positional polymorphism in solids refers to distributions of correlated locally disordered unit cells which reflect, on average, the high-symmetry structure observed in diffraction experiments. The standard theory of electron-phonon interactions is unable to account for the temperature-dependent electronic structure of polymorphous materials. A prime example of such materials is hybrid halide perovskites, for which calculations of band gaps at finite temperatures do not agree with experiment. Here, we develop a systematic and accurate methodology to investigate electron-phonon couplings in complex polymorphous materials, demonstrated through calculations of anharmonic phonons and thermally-induced band gap renormalization for a broad family of halide perovskites. Our approach delivers unprecedented agreement with experiment.