We have found that the polarization dependence of Raman scattering in organic crystals at finite temperatures can only be described by a fourth-rank formalism. This generalization of the second-rank Raman tensor R stems from the effect of off-diagonal components in the crystal self-energy on the light scattering mechanism. We thus establish a novel manifestation of phonon-phonon interaction in inelastic light scattering, markedly separate from the better-known phonon lifetime.
@article{arxiv.2204.12528,
title = {Phonon-phonon interactions in the polarizarion dependence of Raman scattering},
author = {Nimrod Benshalom and Maor Asher and Rémy Jouclas and Roman Korobko and Guillaume Schweicher and Jie Liu and Yves Geerts and Olle Hellman and Omer Yaffe},
journal= {arXiv preprint arXiv:2204.12528},
year = {2023}
}