多铁材料中非共线磁性与电极化耦合机制的理论研究

项目名称： 多铁材料中非共线磁性与电极化耦合机制的理论研究

项目编号： No.11304011

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 数理科学和化学

项目作者： 陈蕾

作者单位： 北京建筑大学

项目金额： 25万元

中文摘要： 本项目将致力于多铁材料中非共线磁性与电极化耦合机制的理论研究。多铁性材料是一类多功能材料，同时具有铁电性和磁性，而且二者之间存在磁电耦合效应，在多铁性材料中可以实现铁电性和磁性的相互调控，因此在自旋电子学，量子调控和其他领域具有非常诱人的实际应用前景。如何理解多铁性材料的磁电耦合机制,寻找设计同时具有磁性和铁电性的材料成为目前多铁性材料研究中的主要问题。本项目将基于电极化和轨道磁矩的贝里相位理论，给出自旋-轨道耦合导致电极化矢量的几何相位形式，利用基于密度泛函理论的第一性原理电子结构计算方法，计算具有非共线磁性的多铁材料中自旋-轨道耦合对电极化矢量的贡献，研究自旋-轨道耦合存在与否对材料电极化矢量的影响，理解多铁性材料中铁电性和磁性的共存耦合机制，以多铁性材料微观机制和物理性质的研究为基础，寻找室温下具有强磁电耦合的新型多铁性材料。

中文关键词： 多铁性材料；第一性原理；非共线；电极化；自旋-轨道耦合

英文摘要： This project concerns the theoretical study of the coupling between noncollinear magnetism and polarization in multiferroics. Multiferroics defined for those multifunctional materials which combine magnetism and ferroelectricity in the same phase. They have tremendous potential for applications in spin electronics,quantum control and other fields, not only because they possess the properties of both parent phenomena, but also because coupling between magnetism and ferroelectricity can lead to additional novel effects. For example, the magnetoelectric effects could yield entirely new device paradigms. However, attempts to make clear the mechanism of magnetoelectric coupling and design multiferroics that combine magnetism and ferroelectricity in the same phase have proved unexpectedly difficult. We are motived to explore the geometric phase form of the polarization caused by spin-orbit coupling, by using the Berry phase theory of polarizaton and orbital magnetization. Using the method of first-principles based on density functional theory(DFT), we could calculate the polarization caused by spin-orbit coupling in multiferroics with noncollinear magnetism, explore the influence of spin-orbit coupling on the polarization in multiferroics. Then we could understand the mechanism of magnetoelectric coupling, and find

英文关键词： multiferroics；first-principles；noncollinear；polarization；spin-orbital coupling