N掺杂6H-SiC电子结构的第一性原理计算

First-principle Calculations of Electronic Structures of Nitrogen-doped 6H-SiC

采用基于密度泛函理论的第一性原理平面波赝势方法，对本征6H-SiC和Si空位、C空位、N掺杂6H-SiC的电子结构及磁性进行了计算。计算结果表明：本征6H-SiC和单一的N掺杂6H-SiC均没有磁性，但可以通过Si空位的引入产生自旋极化。在N和Si空位共掺杂6H-SiC的结构中，Si空位近邻的C原子自旋向上与自旋向下的态密度图明昆不对称，主要是由与Si空位近邻的C-2p轨道的自旋极化引起的。N和2个Si空位共掺杂6H-SiC的结构呈现反铁磁性。

The electronic structures and magnetic properties of intrinsic 6H-SiC and 6H-SiC with Si vacancy （Vsi）, C vacancy （Vc） and nitrogen doping were investigated by a plane wave pseudo-potential method based on the density functional theory. The calculation results show that the intrinsic 6H-SiC and 6H-SiC doped with single N has no magnetism, whereas the one doped with Si vacancy can induce spin-polarization. For 6H-SiC co-doped with N and Si vacancies, an asymmetry between spin up and down appears, which can be mainly attributed to the spin polarization of C-2p orbitals of adjacent Si vacancy. 6H-SiC co-doped with N and two Si vacancies exhibits an antiferromagnetic behavior.