Phase Transition Effect on Ferroelectric Domain Surface Charge Dynamics in BaTiO₃ Single Crystal

The ferroelectric domain surface charge dynamics after a cubic-to-tetragonal phase transition on the BaTiO₃ single crystal (001) surface was directly measured through scanning probe microscopy. The captured surface potential distribution shows significant changes: the domain structures formed rapidly, but the surface potential on polarized domain was unstable and reversed its sign after lengthy lapse; the high broad potential barrier burst at the corrugated domain wall and continued to dissipate thereafter. The generation of polarization charges and the migration of surface screening charges in the surrounding environment take the main responsibility in the experiment. Furthermore, the - domain wall suffers large topological defects and polarity variation, resulting in domain wall broadening and stress changes. Thus, the domain wall has excess energy and polarization change is inclined to assemble on it. The potential barrier decay with time after exposing to the surrounding environment also gave proof of the surface screening charge migration at surface. Thus, both domain and domain wall characteristics should be taken into account in ferroelectric application.