Meron–antimeron annihilation induced by the electric field in a polar meron lattice

Polar topological domain structures may have potential applications in future memory devices. Exploring their dynamical behaviors is paramount to the device design. Here, the meron–antimeron annihilation processes induced by the electric field in ultrathin ferroelectric PbTiO3 films were studied by phase-field simulations. Two types of annihilation behaviors were identified: The merons with central polarizations parallel to the electric field will directly annihilate with their nearby antimerons; those antiparallel to the electric field will first be switched and then annihilate with antimerons. The annihilation ratio of meron–antimeron pairs (MAPs) decreases with the increase in the meron–antimeron distance. During annihilation processes, the positions of antimerons seldom change and the merons approach to antimerons at some critical electric fields. The annihilation probability of a meron is found to be closely related to its topological charge. Specifically, the restoration of an MAP from a partially annihilated state was observed under the decrease in the electric field. These results may have some indications to the development of polar-meron-based memory devices.