中文摘要：

采用基于自旋极化的密度泛函理论的第一性原理方法,使用超原胞模型对Ⅳ族元素掺杂的α-Fe体系α-Fe：X（X=C,Si,Ge）的电子结构和磁学性质进行了系统研究.计算得到了α-Fe体系掺杂前后的能带结构、电子态密度及电荷密度分布等.对计算结果的分析表明：C、Si元素的替位使原胞的体积有所减小,而Ge的替位则导致原胞体积的增大;C和Ge的替位使得电荷密度分布的方向性增强,预示着C和Ge与周围原子相互作用有比较明显的共价性,而Si的替位却对周围电荷密度的影响很小;掺杂时,各替位原子本身基本上都没有表现出磁性,而各Fe原子都保持有磁性,其磁矩都比纯α-Fe中的Fe原子略大.

英文摘要：

The electronic and magnetic properties of α-Fe doped with group-Ⅳ elements（C,Si,Ge） have been studied by employing the first-principles method based on the spin-polarized density functional theory.The band structures,density of states and electronic charge densities were calculated for both the pure α-Fe and the doped systems α-Fe：X（X= C,Si,Ge）.The calculated results showed that：1） the substitution of Fe atom with C or Si leaded to a unit cell volume reduction.The substitution with Ge,on the contrary,leaded to volume expansion;2） the substitution with C or Ge atoms made the charge density distribution more directional around the substitution atoms,suggesting a more remarkable covalent interaction between the corresponding atoms.On the other hand,the substitution with Si atom showed little change on the electronic charge density;3） for the systems with substitution atoms α-Fe：X（X= C,Si,Ge）,the substitution atoms themselves did not show magnetism,however,all the Fe atoms gave magnetic moments which are slightly larger than that of Fe atoms in the pure α-Fe.