2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/122641Transient responses of the electronic excitation and coherent soft phonon are investigated both above and below the ferroelectric phase transition temperature T$_{c}$ in Pb$_{1-x}$Ge$_{x}$Te by using an optical pump-probe technique. The coherent soft mode shows large red-shift and heavily over-damped decay as the temperature approaching T$_{c}$ from the low temperature side and the soft mode disappears above T$_{c}$. The transient electronic response exhibits an abrupt change across T$_{c}$. The critical behaviors of both the phononic and electronic dynamics are interpreted by the ferroelectric phase transition.4 pages, 4 figures, corrected typos, accepted for publication in Physical Review BMaterials Sciencetext