  Optimizing ferroelectrics for contemporary high-frequency applications asks
for the fundamental understanding of ferroelectric switching and domain wall
(DW) motion in ultrafast field pulses while the microscopic understanding of
the latter is so far incomplete. To close this gap in knowledge, ab
initio-based molecular dynamics simulations are utilized to analyze the
dynamics of 180$^\grad# DWs in the prototypical ferroelectric material BaTiO 3
. How ultrafast field application initially excites the dipoles in the system
and how they relax to their steady state via transient negative capacitance are
discussed. Excitingly, a giant boost of the DW velocity related to the
nonequilibrium switching of local dipoles acting as nucleation centers for the
wall movement is found. This boost may allow to tune the local ferroelectric
switching rate by the shape of an applied field pulse.
