The ability to control the domain patterns in ferroelectric nanostructures holds promise as a method to tailor physical properties for specific applications. We proposed a new way to control the domain patterns in ferroelectric nanostructures. Desirable domain patterns can be obtained through different surface charges. The surface charges can be supplied by the atomic and molecular adsorbates on the surfaces of ferroelectric nanostructures.
In our study, 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 abruptly. It makes ferroelectric nanodots experience an unusual transition from a vortex state to a single-domain state. Simulation results also show that regular multi-domain structures can be obtained by means of specified surface charges, which suggests a way to tailor the physical properties for specific applications. Appl. Phys. Lett. 93, 262904 (2008); DOI:10.1063/1.3058821