【摘要】 采用第一性原理计算了Mn掺杂GaN非极性(100)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(100)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.更多还原

【Abstract】 The atomic and electronic structure of Mn-doped GaN(100) 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(100) 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(100) 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.更多还原