用于铁电体复杂畴结构模拟的布朗方程  

Brown’s equation for the simulation of complex domain structures in ferroelectrics

作　　者：欧阳鑫健 张紫阳 张锋[1] 张佳乐 王大威[1] Ouyang Xin-Jian;Zhang Zi-Yang;Zhang Feng;Zhang Jia-Le;Wang Da-Wei(School of Microelectronics,Faculty of Electronics and Information Engineering,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]西安交通大学电子与信息学部微电子学院,西安710049

出　　处：《物理学报》2023年第5期355-364,共10页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11974268,12111530061)资助的课题。

摘　　要：铁电材料在室温下具有可以在外加电场作用下改变方向的自发极化,不同方向的极化在材料内部形成畴结构,会对其物理特性和实际应用具有显著影响.本文将最初用于微磁模拟的布朗方程引入铁电材料的大尺度模拟中,研究其中可能出现的重要畴结构.在以有效哈密顿量方法为基础推导出铁电材料中关于电偶极子的布朗方程后,以BaTiO_(3),PbTiO_(3)块体和SrTiO_(3)/PbTiO_(3)/SrTiO_(3)夹心结构等钙钛矿铁电材料为研究对象,验证了布朗方程的有效性并讨论了其中的多种畴结构,如周期性条带状畴、涡旋型拓扑畴结构等,并与相关实验结果进行了对比分析.Ferroelectric material possesses spontaneous polarization at room temperature,which can be switched by an external electric field.The diverse domain structures within ferroelectric materials,consisting of polarizations in various directions,often significantly affect their physical properties and practical applications.Numerical simulations can aid in comprehending and validating the complex domains observed in experirments.They can also provide guidance for controlling such structures.One popular method for finding dipole configurations is to create an energy model and employ it in Monte-Carlo simulations to find dipole configuration.However,since these simulations usually reaches the ground state of the system(the state with the lowest global energy),they often miss the dipole configurations of interest,such as topological domain structures,which are usually metastable.Here,in order to simulate complex domain,we introduce Brown’s equation,which is originally used for micromagnetic simulation,into the large-scale simulation of ferroelectric materials.Using the effective Hamiltonian as the energy model,we derive the Brown’s equations with respect to the electric dipoles in ferroelectric materials,and invesitgate perovskites such asBaTiO_(3)bulk,PbTiO_(3)bulk,and SrTiO_(3)/PbTiO_(3)/SrTiO_(3)sandwiched structures.We demonstrate the reliability and feasibility of Brown’s equation in ferroelectrics through the simulation of BaTiO_(3)bulk and PbTiO_(3)bulk,which are consistent with experiments.Then,using Brown’s equation derived in our work,we obtain various domain structures in SrTiO_(3)/PbTiO_(3)/SrTiO_(3)sandwiched structures,including periodic stripe domains and vortex domains.The simulation results are compared with related exprimental results.

关 键 词：拓扑畴 布朗方程 钙钛矿 

分 类 号：O469[理学—凝聚态物理] TB34[理学—电子物理学]