【摘要】 采用第一性原理方法,研究了F掺杂四方钙钛矿结构BiFeO₃（T-BiFeO₃）的铁磁性和电子结构。基于TBiFeO₃的四种磁结构,本文计算了两种可能的掺杂位置,确定了最稳定的T-BiFeO_3-xF_x结构。研究发现,不同F的浓度对T-BiFeO₃的总磁矩影响不同,当掺杂为T-BiFeO_2.75F_0.25时,其总磁矩最大,为2μB。进一步分析发现,TBiFeO_3-xF_x的总磁矩主要来源于F原子及其最近邻的Fe原子。电子结构分析表明,费米能级附近的杂质态主要是掺杂后Fe 3d轨道和O 2p轨道向高能级移动而形成的。另外,T-BiFeO_2.75F_0.25具有比较大的极化强度。更多还原

【Abstract】 The ferromagnetic property and electronic structure of tetragonal perovskite BiFeO₃（ T-BiFeO₃）were investigated. Considering two possible doping sites of T-BiFeO₃,the most stable structure of TBiFeO₃ was obtained based on four magnetic structures of T-BiFeO₃. It is found that the total magnetic moment of T-BiFeO₃ with F doped is different with the difference of F concentration. The T-BiFeO_{2. 75}O_{0. 25} has the maximum magnetic moment（ 2 μB） with the increase of F concentration. The total magnetic moment of T-BiFeO_3-xF_x with F doped are mainly coming from the Fe atom and O atoms nearly F after F replacing O. Furthermore,it shows that the impurity states around Fermi are mainly derived from Fe 3d and O 2p orbitals. In addition,the T-BiFeO_{2. 75}O_0.25 has also larger polarization.更多还原