  Developing a microscopic understanding of spin decoherence is essential to
advancing quantum technologies. Electron spin decoherence due to atomic
vibrations (phonons) plays a special role as it sets an intrinsic limit to the
performance of spin-based quantum devices. Two main sources of phonon-induced
spin decoherence - the Elliott-Yafet (EY) and Dyakonov-Perel (DP) mechanisms -
have distinct physical origins and theoretical treatments. Here we show
calculations that unify their modeling and enable accurate predictions of spin
relaxation and precession in semiconductors. We compute the phonon-dressed
vertex of the spin-spin correlation function, with a treatment analogous to the
calculation of the anomalous electron magnetic moment in QED. We find that the
vertex correction provides a giant renormalization of the electron spin
dynamics in solids, greater by many orders of magnitude than the corresponding
correction in vacuum. Our work demonstrates a general approach for quantitative
analysis of spin decoherence in materials, advancing the quest for spin-based
quantum technologies.
