摘要
采用第一性原理计算了Mn掺杂GaN非极性(100)薄膜的原子和电子结构.结果表明弛豫后表层Ga原子向体内移动,与Ga原子成键的表层N原子向体外移动,表层Ga-N键长收缩并扭转.通过对Mn原子掺杂在不同层总能量的比较,发现GaN(100)薄膜中Mn原子更容易在表层掺杂.弛豫后,掺杂在表层的Mn原子及与Mn原子成键的表层N原子都向体内发生很小的移动,Mn-N键没有发生明显扭转,但是弛豫后N原子向Mn原子靠近,Mn-N键收缩.Mn原子的掺杂使得Mn3d与N2p轨道杂化,产生自旋极化杂质带,自旋向上的能带占据费米面.掺杂后的薄膜表现为半金属性,适合于自旋注入.
The atomic and electronic structure of Mn-doped GaN（100） nonpolar film was investigated using first-principles calculations.The results show that the surface Ga atom moves inward and N atom moves outward and the consequence of relaxation results in the reduction of the bond length of the Ga-N dimers and bond buckling.To determine the energetically most favorable doping site in the（100） film,we also calculated the total energy for Mn doping.It was found that the site closest to the surface is always favored.The Mn atom and N atom moves inward slightly,while the Mn-N bond length is reduced as the Ga-N bond at the surface.The phenomena of the buckling of Ga-N bond is not observed for Mn-N bond.The results reveal a spin polarized impurity band in band structure of Mn-doped GaN（100） film due to hybridization of Mn3d and N2p orbitals.The Mn impurity bands appear in the gap of spin-up bands,meaning that the film material is half metallic and suited for spin injectors.
出处
《南京师大学报（自然科学版）》
CAS
CSCD
北大核心
2011年第2期34-38,共5页
Journal of Nanjing Normal University(Natural Science Edition)
基金
江苏省高校自然科学基金(09KJB140004)
关键词
稀磁半导体
薄膜
电子结构
几何结构
diluted magnetic semiconductor
film
electronic structure
geometric structure
