Epitaxy surface effect on the critical properties of a ferroelectric thin film

The characteristic properties, the critical surface transverse field Omega(sc) and the Curie temperature T-c, for an N-layer ferroelectric thin film with epitaxy surface layers N-s described by the transverse field Ising model have been studied by the differential operator technique within the framework of effective-field theory with correlations. The analytical equation for the phase diagrams of ferroelectric thin films is derived. The surface transverse field Omega(s) dependence of the Curie temperature T-c in the ferroelectric thin film with different epitaxy surface layers is calculated. Meanwhile the epitaxy surface layer number N-s dependence of the critical surface transverse field Omega(sc) and the Curie temperature T-c is also examined. The results show that the critical properties depend heavily on modifications of interchange interactions and transverse fields in the epitaxy surface layer.