Mn掺杂LiZnN新型稀磁半导体磁电性质的第一性原理计算  

First-principles Calculations of Magnetoelectric Properties of New Diluted Magnetic Semiconductor Mn-doped LiZnN

作　　者：徐建 杜成旭 杜颖妍 贾倩 刘洋华 毋志民 XU Jian;DU Chengxu;DU Yingyan;JIA Qian;LIU Yanghua;WU Zhimin(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

出　　处：《计算物理》2018年第6期711-719,共9页Chinese Journal of Computational Physics

基　　金：重庆市基础与前沿研究计划项目(cstc2014jcyjA50005);重庆师范大学教学名师培育计划项目(02030307-0003);重庆科技学院院士专家重点实验室合作项目(CQKL-1505);重庆高校创新团队计划项目(CXTDX201601016);重庆市研究生科研创新项目(CYS17179);国家大学生创新创业训练计划项目(201710637003)资助

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方法,对纯LiZnN、Mn掺杂LiZnN及Li不足和过量时Mn掺杂LiZnN体系进行几何结构优化,分析体系的电子结构、半金属性和磁电性质.结果表明,Mn的掺入使体系产生自旋极化杂质带,自旋极化率为100%,表现出半金属铁磁性,且形成较强的Mn—N共价键.当Li不足时,Mn—N键的共价性最强,键长变短,体系半金属性明显增强,形成能最低,结构最稳定.Li过量时,体系半金属性消失,表现为金属性,杂质带宽度增大,体系导电能力增强.表明Mn掺杂LiZnN新型稀磁半导体可以通过Mn的掺入和改变Li的含量来实现磁性和电性的分离调控.掺杂体系的基态均为铁磁性,其净磁矩主要由Mn原子贡献,通过海森堡模型计算发现,Li空位可以有效提高体系的居里温度.Electronic structures,half-metallic and magnetoelectric properties of pure LiZnN,Mn-doped LiZnN and Mn-doped LiZnN with excess and deficient of Li are geometrically optimized and calculated by using first principle density functional theory based on full potential linearized augnmented plane wave method.It reveals that doping of Mn leads to a spin polarized impurity band with a spin polarization of 100%.The system exhibits half-metallic ferromagnetism properties,and strong Mn-N covalent bonds are formed.In Li vacancy system,covalent bonds of Mn-N bonds are strongest.Their bond lengths become shorter,and half-metallic is obviously enhanced.Formation energy of the system decrease,which indicates that the structure is more stable.In Li excess system,half-metallic property of the system disappears and becomes metallic.Impurity band width increases and conductivity of the system increases,but interaction of Mn-N bond becomes weaker.It indicates that magnetic and electrical properties of Mn-doped LiZnN new diluted magnetic semiconductor can be regulated separately via Mn isovalent doping and off-stoichiometry.Ground state of Mn doped LiZnN system is ferromagnetic,and net magnetic moment of the system is mainly contributed by Mn atoms.It is found with Heisenberg model that Li vacancy system inereases Curie temperature.

关 键 词：Mn掺杂LiZnN 第一性原理 电子结构 铁磁性 

分 类 号：O472[理学—半导体物理] O469[理学—物理]