We propose that phonons coupled to electrons play an important role in both the fundamental phenomenology of electron spin resonance as well as the interpretation of such measurements. By including spin-dependent electron-phonon interactions originating from spin-orbit coupling, we demonstrate that the g-factor acquires emergent temperature dependencies that are in excellent agreement with experimental observations. Moreover, we predict that at low temperatures, the g-factor will exhibit a non-trivial dependence on the magnetic field, indicating a dynamic property that has not been previously considered in electron-phonon systems. We further predict the influence of phonons to be negligible at very low and very high temperatures, with the former requiring experimental verification.
@article{arxiv.2509.07859,
title = {Temperature and magnetic field dependent $g$-factors in electron spin resonance spectroscopy},
author = {Sebastian Kalhöfer},
journal= {arXiv preprint arXiv:2509.07859},
year = {2025}
}