(1. 河南理工大學(xué) 材料科學(xué)與工程學(xué)院 環(huán)境友好型無機材料重點實驗室培育基地，焦作 454000； 2. 大連交通大學(xué) 材料科學(xué)與工程學(xué)院，大連 116028； 3. 河南理工大學(xué) 材料科學(xué)與工程學(xué)院物理與電子信息學(xué)院，焦作 454000)
摘 要: 采用基于密度泛函理論的第一性原理平面波贗勢方法研究Co摻雜4H-SiC的電子結(jié)構(gòu)和磁性。計算結(jié)果表明：Co摻雜引入了空穴，產(chǎn)生自旋極化。Co摻雜4H-SiC的價帶頂和導(dǎo)帶底分別由Co的3d態(tài)和C的2p態(tài)占據(jù)，而Si的2p軌道作用較小。通過計算10種可能的摻雜位置，確定了鐵磁性最穩(wěn)定的組態(tài)。由于Co0:3d-C:2p-Co6:3d鏈之間存在一定的耦合關(guān)系，Co與C原子間強烈的d-p軌道雜化使得Co摻雜4H-SiC處于較穩(wěn)定的鐵磁基態(tài)。Co的引入使得基體空穴增加，缺陷調(diào)節(jié)下空穴載流子的遠(yuǎn)程交換(RKKY)機制導(dǎo)致了鐵磁性的出現(xiàn)。
關(guān)鍵字: 稀磁性半導(dǎo)體；電子結(jié)構(gòu)；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
