  Ferroelectric vortices formed through complex lattice-charge interactions
have great potential in applications for future nanoelectronics such as
memories. For practical applications, it is crucial to manipulate these
topological states under external stimuli. Here, we apply mechanical loads to
locally manipulate the vortices in a PbTiO3-SrTiO3 superlattice via atomically
resolved in situ scanning transmission electron microscopy. The vortices
undergo a transition to the a-domain with in-plane polarization under external
compressive stress and spontaneously recover after removal of the stress. We
reveal the detailed transition process at the atomic scale and reproduce this
numerically using phase-field simulations. These findings provide new pathways
to control the exotic topological ferroelectric structures for future
nanoelectronics and also valuable insights into understanding of lattice-charge
interactions at nanoscale.
