温度梯度铁电薄膜中的量子起伏效应研究

在平均场近似的理论框架下，采用拓展的横场伊辛模型理论，通过研究不同边界条件下的BaTiO3温度梯度铁电薄膜内的极化分布来探讨薄膜内部的量子起伏效应．研究表明：量子起伏效应对温度梯度铁电薄膜的极化性质有重要影响，它显著降低了薄膜内的极化强度；量子起伏效应在薄膜低温区的影响比在高温区的影响显著；对固定边界条件下的薄膜的影响要高于对自由边界条件下的薄膜的影响；对下温度梯度铁电薄膜的影响要大于对上温度梯度薄膜的影响；当量子起伏效应足够强时，下温度梯度铁电薄膜内的极化分布将会出现一个临界点，临界点前后极化偏移的方向发生了改变．

Investigations on Quantum Fluctuation Effects in Temperature-graded Ferroelectric Thin Films

In the framework of the mean field approximation, a developed transverse model was adopted. The quantum fluctuation effect was discussed through the investigation of polarization distribution in BaTiO3 temperature-graded ferroelectric thin films under different boundary conditions. It was shown that quantum fluctuation had important influence on polarization properties, which obviously decreased the po- larization in films. Its influence was more obvious in low temperature region than in high temperature re- gion. It had more influence on CBC film than on FBC film. It had more obvious influence on DTF than on UTF. When the quantum fluctuation effect was strong enough, there appeared a critical point in polarization distribution in DTF, which changed the direction of the polarization offset.