Soft-mode driven dynamics in ferroelectrics -new insight from ultrafast terahertz and x-ray experiments Thomas Elsaesser, Giulia Folpini, Carmine Somma, Klaus Reimann, Marcel Holtz, Antonio-Andres Hernandez Salvador, Christoph Hauf and Michael Woerner EPJ Web Conf., 205 (2019) 04001 Published online: 16 April 2019 DOI: 10.1051/epjconf/201920504001