First-principles many-body calculations of polarons in materials*

A polaron is a particle together with the induced polarization of the surrounding lattice. The description of a polaron in first principles started with Sio et. al. [Phys. Rev. B 99, 235139 (2019); Phys. Rev. Lett. 122, 246403 (2019)], and recently Lafuente-Bartolome et. al. developed the theory of first-principles many-body calculations of polarons at all couplings and applied it to LiF [Phys. Rev. B 106, 075119 (2022); Phys. Rev. Lett. 129, 076402 (2022)]. Based on these we can systematically calculate polaronic corrections to phonon-induced band energy renormalization beyond perturbation theory since we can apply the method to various different groups of materials with different strengths of electron-phonon interactions, calculating Fan-Migdal, Debye-Waller, polaron contributions to polaron formation energies. We also identify localized polaron wavefunctions and project them into Bloch wavefunction and normal modes.