The effect of the surface electrode distributions on domain structures of ferroelectric thin films

Various domain structures in ferroelectric thin films with four different surface interdigital electrodes are simulated based on the time-dependent Ginzburg-Landau method. The four different electrode distributions are that (a) both surfaces are symmetrically arranged interdigital electrodes, (b) top surface is covered with interdigital electrode while bottom surface is covered with full electrode, (c) both surfaces are alternately arranged interdigital electrodes and (d) top surface is covered with interdigital electrodes while bottom is not covered with electrode. These electrode distributions could be converted to corresponding electrical boundary conditions of the phase field equations. Compared with ideal short circuit and open circuit electrical boundary conditions, there are some special domain structures (vortices, flux-closure structures and a/c domains) due to the change of depolarization electric energy and Landau energy with different surface electrodes. The domain structures in ferroelectric thin films have an obvious size effect with the surface interdigital electrodes. These results indicate we can obtain the various domain structures of ferroelectric thin films by turning different surface electrode distributions.