Effects of interface dislocations on properties of ferroelectric thin films

摘要

Effects of interfacial dislocations on properties of thin-film ferroelectric materials, such as the self-polarization distribution, Curie temperature, dielectric constant and the switching behaviors, are investigated via the system dynamics based on the Landau-Devonshire functional. Dislocation generation in the film is found to reduce the overall self-polarization and the Curie temperature. The spatial variations are both very strong, particularly in the immediate neighborhood of the dislocation cores. In agreement with previous results based on a stationary model, a dead layer exists near the film/substrate interface, in which the average self-polarization is much reduced. Moreover, it is evident from our results that interface dislocations play an important role in suppressing the remnant polarization and the coercive field of the polarization.