非化学配比的非晶过渡金属氧化物磁性半导体的微观结构与磁性调控

项目名称： 非化学配比的非晶过渡金属氧化物磁性半导体的微观结构与磁性调控

项目编号： No.11504203

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 胡树军

作者单位： 山东大学

项目金额： 24万元

中文摘要： 与晶态氧化物磁性半导体相比，ZnCoO、TiCoO等非化学配比的非晶过渡金属氧化物磁性半导体具有高饱和磁化强度、高居里温度以及高自旋极化率，有望成为新型的自旋电子学材料。非晶过渡金属氧化物在实验上很难表征微观结构，其组分、微观结构与磁性起源之间的关联亟待研究。针对以上问题，本项目拟(1)结合分子动力学模拟和第一性原理计算方法，确定实验上发现的具有高饱和磁化强度、高居里温度以及高自旋极化率的非晶过渡金属氧化物磁性半导体的微观结构；（2）研究微观结构与带边局域态的关系,建立带边局域态传递磁交换作用的理论模型；（3）研究氧离子与金属离子的非化学配比对非晶过渡金属氧化物的微观结构和磁性的调控机制；（4）优化非晶过渡金属氧化物的原子组分和微观结构，获得更高磁化强度、居里温度和自旋极化率的非晶过渡金属氧化物。该项目的实施有望为设计高居里温度、高自旋极化率的新型磁性半导体材料提供理论指导。

中文关键词： 磁性调控；过渡金属氧化物；分子动力学模拟；非晶材料；非化学配比

英文摘要： Compared with the crystalline oxide magnetic semiconductors, high Curie temperature, high saturation magnetization and high degree of spin polarization are possessed by non-stoichiometric amorphous transition metal oxides (ATMO) magnetic semiconductors, such as ZnCoO and TiCoO, which belong to a new type of spintronics material. However, it is difficult to experimentally characterize the microstructure of ATMO, and it is urgent to study the correlation among the atomic components, the microstructure and the origin of ferromagnetism. In response to these problems, the current project will finish the following research tasks. (1) By performing the molecular dynamics simulations in conjunction with the first-principles calculations, we will study the microstructure of experimentally prepared ATMO with high Curie temperature, saturation magnetization and degree of spin polarization. (2) We will investigate the relation between the microstructure and the localized states near the band gap. Then a theoretical model for the exchange interactions mediated by the localized states will be established. (3) We will reveal the microstructure and magnetization dependence on the stoichiometry of component ions. (4) By optimizing the atomic components and the microstructure, we will search for the ATMO with even higher Curie temperature, magnetization and degree of spin polarization. Our research will provide the theoretical support for preparing the novel magnetic semiconductors.

英文关键词： magnetic control;transition metal oxide;molecular dynamics simulation;amorphous materials;non-stoichiometry