富镓Ga_nAs团簇稳定性及缺陷特性的密度泛函理论研究  

Density functional theory study on stability and defect feature of Ga-rich GanAs（n =1～9） clusters

作　　者：马德明[1] 乔红波[1] 李恩玲[1] 施卫[1] 马优恒[2] 

机构地区：[1]西安理工大学应用物理系,西安710054 [2]西安应用光学研究所,西安710065

出　　处：《原子与分子物理学报》2014年第2期223-228,共6页Journal of Atomic and Molecular Physics

基　　金：国家自然科学基金(50837005);陕西省教育厅自然科学基金(2010JK743);教育部博士学科点专项科研基金(20116118110014);陕西省国际合作与交流科技计划项目(2012KW-04)

摘　　要：采用基于密度泛函理论（DFT）的第一性原理对富镓中性GanAs（n=1～9）团簇的稳定性及缺陷特性进行了研究.结果表明,随着总原子数的增大,各基态团簇结合能的二阶差分值和团簇能隙差均呈奇偶交替变化规律,总原子数为奇数的团簇比总原子数为偶数的团簇稳定;部分团簇的能隙差小于砷化镓材料的禁带宽度,为砷化镓材料缺陷的研究提供了帮助,其中GaAs团簇缺陷中的VAsVGa缺陷导致能带中的T点处的带隙宽度减小,其最低施主缺陷能级位于导带底以下0.39eV,该值接近于EL6缺陷能级的实验值;团簇各基态结构的振动频率均在THz频段,从而为砷化镓材料的THz波辐射和缺陷的THz波检测提供了依据.The stability and defect feature of Ga-rich neutral GanAs（n=1～9） clusters have been studied by using first-principles based on density functional theory （DFT）.Our calculations reveal that secondorder difference values of the binding energy and energy gaps of the ground-state clusters all show a certain law of even-odd alternation with the increase of the number of total atoms,the odd-numbered clusters are more stable than the even-numbered ones.The energy gaps of some ground-state clusters are less than GaAs materials＇ band gap,so it will provide any help for defect research of GaAs materials.The VAsVGa defects lead to decreasing band gap at the T point in the GaAs cluster defects,the lowest donor defect level locates at 0.39eV below the bottom of conduction band,which is very close to the experimental result of the EL6 defect level.The ground-state clusters are potential to defect detection and THz wave radiation in the GaAs materials owing to the vibrational frequencies of the ground-state clusters are in the terahertz frequency band.

关 键 词：密度泛函理论 GanAs团簇 结构稳定性 VAsVGa缺陷 

分 类 号：O561.1[理学—原子与分子物理]