Study of defect-layers effect in ferroelectric thin film with transverse ising model

By taking into account the two-spin interaction in the transverse Ising model (TIM), the influence of the defect layers (including J _B and Ω _B) on the polarization and Curie temperature are calculated numerically, within the framework of the decoupling approximation under Green's function. The numerical results show that the polarization and Curie temperature will both become large sensitively due to the large values of J _B and the small value of Ω _B of the defect layers. Meanwhile, the dependence of the crossover values of the exchange interaction J _A, the transverse field Ω _A of the bulk material on the exchange interaction J _B and the transverse field Ω _B of the defect layers are shown in 3-Dimensional (3-D) figures for the first time. Moreover, the transition features of the ferroelectric thin film with defect layers are presented. © 2011 Chinese Physical Society and IOP Publishing Ltd.