(1. 河南理工大学 材料科学与工程学院 环境友好型无机材料重点实验室培育基地，焦作 454000； 2. 大连交通大学 材料科学与工程学院，大连 116028； 3. 河南理工大学 材料科学与工程学院物理与电子信息学院，焦作 454000)
摘 要: 采用基于密度泛函理论的第一性原理平面波赝势方法研究Co掺杂4H-SiC的电子结构和磁性。计算结果表明：Co掺杂引入了空穴，产生自旋极化。Co掺杂4H-SiC的价带顶和导带底分别由Co的3d态和C的2p态占据，而Si的2p轨道作用较小。通过计算10种可能的掺杂位置，确定了铁磁性最稳定的组态。由于Co0:3d-C:2p-Co6:3d链之间存在一定的耦合关系，Co与C原子间强烈的d-p轨道杂化使得Co掺杂4H-SiC处于较稳定的铁磁基态。Co的引入使得基体空穴增加，缺陷调节下空穴载流子的远程交换(RKKY)机制导致了铁磁性的出现。
关键字: 稀磁性半导体；电子结构；磁性；第一性原理；4H-SiC
（1. Cultivating Base for Key Laboratory of Environment-Friendly Inorganic Materials in Henan Province, School of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China; 2. Liaoning Key Materials Laboratory for Railway, School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028, China; 3. School of Physics & Electronic Information Engineering, Henan Polytechnic University, Jiaozuo 454000, China）
Abstract:Electronic and magnetic properties of Co doped 4H-SiC are researched by use of the first-principle plane wave pseudo-potential method based on density functional theory. Ten kinds of doping position were calculated and the most stable configuration was found out. The calculation results show that spin-polarization appears in one Co atom doped 4H-SiC, which is due to the introduction of vacancy. The top of valence band and the bottom of the conduction band are mainly contributed by Co-3d, C-2p orbitals, with small contribution of Si-2p. Ferromagnetism order is activated by Co doping via a Co0:3d-C:2p-Co6:3d coupling chain. Hybridization occurs between p-d orbitals. The doped Co ion will induce additional holes carrier into the 4H-SiC. Therefore, the mechanisms for stabilizing the ferromagnetic state in Co doped 4H-SiC based on defect interaction and Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction.
Key words: dilute magnetic semiconductors; electronic structure; magnetism; first principle; 4H-SiC
