Self-Organized Ferroelectric Domains Controlled by a Constant Bias from the Atomic Force Microscopy Tip

The ferroelectric polarization switching along an external electric field is most important for the applications of ferroelectric memories and piezoelectric sensors and actuators; however, the depolarization commonly occurs randomly and cannot be controlled exactly until now. Here, a tip bias introduces the polarization switching and a ∼10 μm-scale domain in a triglycine sulfate crystal, and then the polarization backswitching as a special depolarization introduces a series of ordered granular domains along a line being parallel to the c axis and through the tip which divides the original domain to two similar parts. Such backswitching is controlled by the surface charge change as a result of the interplay among polarization charges, mobile H⁺ ions at the surface, and the strong crystal anisotropy. The self-organized ferroelectric domains offer us a new freedom to design novel ferroelectric or piezoelectric devices in future.