2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/24855We propose an efficient approach within the density-functional theory to determine the phonon structure of infinite solids under finite electric fields. We apply this approach to technological SrTiO$_3$, predicting many unusual properties--including a giant frequency shift, anomalous piezoelectric response, as well as striking dielectric tunability. A microscopic understanding for individual phonon modes under finite electric fields is also provided.4 pages, 2 figuresMaterials Sciencetext