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Mg2Si:Fe 电子结构及磁性的理论研究
廖杨芳,谢泉,肖清泉,项飞羽,杨真
0
(贵州大学 大数据与信息工程学院新型光电子材料与技术研究所&贵州师范大学 物理与电子科学学院)
摘要:
采用基于密度泛函理论的第一性原理赝势平面波方法研究了 Mg2Si:Fe 体系的电子能带结构、 态密度和磁性.结果表明: 掺入的 Fe 原子优先占据晶格中的空隙位, 也可能代替晶格中的 Mg 位. 从能带结构和态密度可以看出, 当 Fe 原子位于晶格中空隙位时, 系统显示出金属性; 当 Fe 占据 Mg 位置时, 对于自旋向上电子态, 体系有一带隙存在, 系统呈现明显的半导体特性; 对于自旋向下电子态,Fe 的替位掺杂在该体系内引入新的杂质能级, 杂质能级与导带价带分离, 且100% 自旋极化.两种位置的杂质, 上自旋电子和下自旋电子的态密度均明显不对称, 诱导出铁磁性, 且铁磁性主要由于 Fe 的3d 态电子诱导产生.Fe 位于空隙位时,Fe 原子的磁矩为1.69μB ;Fe 占据 Mg位时, Fe 原子的磁矩为1.38μB , 说明原子磁矩与其所占位置和配位情况有关.
关键词:  Mg2Si  Fe 掺杂  电子结构  磁性  第一性原理计算
DOI:
基金项目:
Theoretical Studyonthe Electronic Structures and Magnetismof Mg2Si:Fe
LIAO Yangfang,XIE Quan,XIAO Qingquan,XIANG Feiyu,YANG Zhen
(College of Big Data and Information Engineering ,Guizhou University & College of Physics and Electronic Sciences ,Guizhou Normal University)
Abstract:
The electronic band structures, densities of states and magnetism of Mg2Si:Fe were investigated using a first principles plane-wave pseudopotential method based on the density functional theory. The results show that Fe atom is expected to be located at the interstitial site preferentially and perhaps at the Mg site in Mg2Si lattice. Calculations of the energy bands and densities of states show that system of Mg2Si:Fe presents the characteristic of metal when Fe atom is located at the interstitial site. However, Mg2Si:Fe offers the half-metal property when Fe atom substitutes for Mg. For both of the cases, the distributions of spin-projected total density of states are obviously asymmetric, so the ferromagnetism is induced. The ferromagnetism of Mg2Si: Fe is mainly due to the electrons of Fe 3d states. The calculated local magnetic moments are 1.69μB for Fe at interstitial site and 1.38μB for Fe at Mg site, respectively, which indicates that the magnetic moment of Fe atom strongly depends on the site occupied by the atom in the unit cell and on the configuration of the nearest neighbors.
Key words:  Mg2Si, Fe-doped, bandstructures, magnetism,thefirst principlecalculations

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