Domain control in ferroelectric nanodots through surface charges

Stable polarization distributions of freestanding ferroelectric nanodots with different surface charges are investigated numerically using a phase field model. The out-of-plane components of polarizations are found to be proportional to the density of surface charge. When the density of surface charge exceeds a critical value, the in-plane components of polarizations disappear. It makes ferroelectric nanodots experience an unusual transition from a vortex state to a single-domain state. Simulation results also show that regular multidomain structures can be obtained by means of specified surface charges, which suggests a way to tailor the physical properties for specific applications.