物理化学学报 >> 2010, Vol. 26 >> Issue (10): 2801-2806.doi: 10.3866/PKU.WHXB20101021

量子化学及计算化学 上一篇    下一篇

基于第一性原理的Mn-AlN 和Cr-AlN 的半金属性质

樊玉勤1, 何阿玲2   

  1. 1. 重庆科技学院数理学院, 重庆 401331;
    2. 重庆大学物理学院, 重庆 400044
  • 收稿日期:2010-04-15 修回日期:2010-06-29 发布日期:2010-09-27
  • 通讯作者: 樊玉勤 E-mail:g.y.wind@163.com
  • 基金资助:

    重庆市自然科学基金(CSTC2007BB4137) 资助项目

Half-Metallic Properties of Mn-AlN and Cr-AlN Based on First-Principles

FAN Yu-Qin1, HE A-Ling2   

  1. 1. College of Mathematics and Physics, Chongqing University of Science and Technology, Chongqing 401331, P. R. China;
    2. College of Physics, Chongqing University, Chongqing 400044, P. R. China
  • Received:2010-04-15 Revised:2010-06-29 Published:2010-09-27
  • Contact: FAN Yu-Qin E-mail:g.y.wind@163.com
  • Supported by:

    The project was supported by the Chongqing Natural Science Foundation, China (CSTC -2007BB4137).

摘要:

基于密度泛函理论(DFT) 的第一性原理方法, 在广义梯度近似(GGA) 下研究了纤锌矿Mn-AlN 和Cr-AlN 的能带结构、态密度与磁学等性质. 结果表明, Mn-AlN 和Cr-AlN 的半金属能隙都随着杂质浓度的增大而减小. 原因可能是随着Mn/Cr 掺杂浓度的增大, 杂质原子间相互作用增强, Mn/Cr3d 与N2p 杂化减弱, 使得自旋交换劈裂变小, 从而半金属能隙变窄. 在同等掺杂浓度下, Mn-AlN 比Cr-AlN 的半金属能隙大. 这是因为Mn3d 态能级比Cr3d 态能级低, Mn3d 与N2p 杂化更强, 导致自旋交换劈裂更大, 自旋向下子带的导带底相对远离费米能级, 因此Mn-AlN 的半金属能隙较大.

关键词: AlN, 过渡金属掺杂, 半金属, 能带结构, 态密度

Abstract:

The band structures, density of states (DOS), and magnetic properties of wurtzite Mn-AlN and Cr-AlN were studied using density functional theory (DFT) with the generalized gradient approximation (GGA) for the exchange-correlation potential. The results indicate that the half-metallic gap of Mn-AlN and Cr-AlN decreases as the Mn/Cr doping concentration increases. This probably results froman increase in the interaction between Mn and Mn or Cr and Cr atoms and a decrease in the hybridization of Mn/Cr 3d and N 2p states with increasing the Mn/Cr doping concentration, which results in a smaller spin-exchange splitting so the half-metallic gap is reduced. Additionally, with the same doping concentration, the half-metallic gap of Mn-AlN is larger than that of Cr-AlN. This is due to the lower Mn 3d states compared to the Cr 3d states and the hybridization of Mn 3d and N 2p states being stronger in Mn-AlN, which leads to a larger spin-exchange splitting so the conduction band minimum of the down spin bands moves far away fromthe Fermi level and the half-metallic gap of Mn-AlN becomes larger.

Key words: AlN, Transition metal doping, Half-metal, Band structure, State density

MSC2000: 

  • O641