稀土元素Eu掺杂LiCaN新型稀磁半导体的磁光电性质调控  

Regulation of magnetic,optical and electrical properties of rare earth element Eu-doped LiCaN new diluted magnetic semiconductor

作　　者：刘明 肖竞争 周芊岍 杨彩艺 李越 丁守兵 毋志民 LIU Ming;XIAO Jing-Zheng;ZHOU Qian-Qian;YANG Cai-Yi;LI Yue;DING Shou-Bing;WU Zhi-Min(Chongqing Key Laboratory of Photoelectric Functional Materials,College of Physics and Electronic Engineering,Chongqing Normal University,Chongqing 401331,China)

机构地区：[1]重庆师范大学物理与电子工程学院光电功能材料重庆市重点实验室,重庆401331

出　　处：《原子与分子物理学报》2022年第1期143-150,共8页Journal of Atomic and Molecular Physics

基　　金：重庆市自然科学基金面上项目(cstc2019jcyj-msxmX0251);重庆市大学生创新创业训练计划项目(S201910637024)。

摘　　要：采用基于密度泛函理论的第一性原理平面波超软赝势法,对新型稀磁半导体Li_(1)±y(Ca_(1-x)Eu_(x))N(x=0,0.125;y=0,0.125)进行几何结构优化,计算并分析了体系的电子结构、磁性和光学性质.结果表明:可以通过掺入稀土元素Eu和改变Li的计量数来调控体系的磁性和电性.Eu掺入后,带隙值减小,在费米能级附近发生了强烈的p-f轨道杂化,体系获得了比Mn掺LiCaN更大的磁矩,磁矩主要来源于Eu4f态能级的引入.Li缺陷时,体系变为半金属性,杂化作用减弱,磁矩减小.Li过量时,体系发生了杨-泰勒效应,能带重组,体系呈金属性,磁矩最大.对比光学性质发现,介电函数虚部、复折射率函数、吸收函数和光电导率函数实部均受到Li计量数的影响,扩大了电磁波的吸收范围,掺杂体系吸收峰具有明显的蓝移效应,Li计量数的改变使体系具有更宽的等离子体振荡范围而Li过量时等离子体共振频率最大.The geometric structures of new diluted magnetic semiconductor Li _(1)±y(Ca _(1-x) Eu _(x))N(x=0,0.125;y=0,0.125)were optimized by using the first-principle density functional theory based on augmented plane wave method.The electronic structures,magnetic and optical properties were calculated and discussed in details.The results show that the magnetic and electrical properties of the doped systems can be separately regulated by rare earth element Eu doping and Li off stoichiometry.When Eu doped in the system,the impurity band merges in the conduction and valence bands,and the band gaps of the system decrease.The strong p-f orbital hybridization near the Fermi Energy leads to much larger magnetic moments than that of Mn doped LiCaN.The magnetic moments mainly come from the introduction of the Eu 4f state.The Li insufficient compound becomes half-metallic ferromagnetism.The hybridization is weakened,and the magnetic moments decrease.In Li excess compound,Jahn-Teller effect leads to band reorganized,and the system becomes metallicity.The magnetic moments are increased to the maximum.The comparison of optical properties indicates that the imaginary part of dielectric function,complex refractive index function,optical absorption function and the real part of photoconductivity are all affected by Li stoichiometry,and the absorption range of electromagnetic wave is expanded.The energy loss functions of the doped systems show obvious blue-shift effect,and the oscillating range of plasma becomes wider in Li excess and insufficient compounds.The plasma resonant frequency is the largest when Li is excessive.

关 键 词：第一性原理 Eu掺LiCaN 电子结构 光学性质 

分 类 号：O472[理学—半导体物理]