基于第一性原理的Mn-AlN和Cr-AlN的半金属性质.pdf

物理化学学报( Wuli Huaxue Xuebao)
October
Acta Phys.-Chim.Sin,2010,26(10:2801-2806
Articlel
www.whxb.pku.edu.cn
基于第一性原理的Mn-AIN和 CR-AN的半金属性质
樊玉勤*何阿玲2
(重庆科技学院数理学院,重庆401331;2重庆大学物理学院,重庆40004
摘要:基于密度泛函理论(DFI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-AIN
的能带结构、态密度与磁学等性质.结果表明,Mn-AN和Cr-AN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増强,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-AIN比Cr-AIN的半金属能隙大.这是因为Mn3d态能
级比Cr3以态能级低,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-AIN的半金属能隙较大
关键词:AN;过渡金属掺杂;半金属;能带结构;态密度
中图分类号:O641;0474
Haif-metallic Properties of MN-AIN and CR-ALN Based on First-principles
FAN YU-QIN."HE A-ling'
(College of Mathematics and Physics, Chonging University of Science and Technology, Chongging 407331, P.R. China;
College of Physics, Chongqing University, Chongging 400044, P. R. China)
Abstract: The band structures, density of states(DOS) and magnetic properties of wurtzite MN-AIN and CR-AIN
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-AIN and CR-ALN decreases as the
Mn/Cr doping concentration increases. This probably results from an 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-AIN is larger than that of CR-AIN. 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-AIN,
which leads to a larger spin-exchange splitting so the conduction band minimum of the down spin bands moves far
away from the Fermi level and the half-metallic gap of MN-AIN becomes larger.
Key Words: AIN; Transition metal doping; Half-metal; Band structure; State density
自旋电子学是一门最新发展起来的涉及磁学、型的功能磁电子材料,由于其能带结构的费米面处
电子学以及信息学的交又学科,它可同时利用电子只有一个自旋方向的电子,传导电子的极化率达到
的电荷和自旋特性来进行信息的存储和处理.自旋100%,是理想的自旋电子学材料,因而半金属材料
电子器件与普通半导体电子器件相比具有非易失已成为材料研究领域中的热点之一别.目前,已有
性、低功耗和高集成度等优点.半金属材料是一种新理论预测磁性过渡金属或稀土金属元素部分取代
eceived: Apnl I
September 10, 2010
correspondingauthorEmail:g.y.wind@163.com;tcl:+86-23-65023915
The project was supported by the Chongging Natural Science Foundation, China(CSTC-2007BB4137)
重庆市自然科学基金(CSTC2O07BB4137)资助项目
(C Editorial office of Acta Physico-chimica Sinica