双钙钛矿SrKFeWO6的电子结构与磁性

基于密度泛函理论框架下的第一性原理，采用考虑在位库仑作用的广义梯度近似（GGA＋U）下的投影缀加波（PAW）方法，研究了具有双钙钛矿结构的Sr₂FeWO₆和SrKFeWO₆材料的晶体结构、电子结构以及磁性性质.结构优化表明，K空穴掺杂稳定了FeO₆及WO₆八面体结构，Fe-O-W键角更加接近180°，有利于Fe-O-W-O-Fe超交换作用；对电子结构分析发现掺杂元素本身对总态密度贡献很小，空穴（p 关键词： 电子结构 磁性 6')" href="#">SrKFeWO₆ 双钙钛矿

Electronic structure and magnetism of the double perovskite SrKFeWO6

The crystal structure，electronic structure and magnetism of the double perovskite Sr₂FeWO₆ and SrKFeWO₆ have been investigated under the framework of density functional theory (DFT) with the generalized gradient approximation taking into account the on-site Coulomb energy (GGA+U) using the projected augmented wave (PAW) method. Structure relaxation results show that K doping of Sr₂FeWO₆ stabilizes FeO₆，WO₆ octahedra and makes the Fe—O—W angles close to 180°，indicating the enhancement of superexchange interaction. From the electronic structure calculation，it was found that the contribution to the total density of states (DOS) from K itself is small. Due to the K doping，the valence and magnetic moment of B-site cation Fe are enhanced and the hybridization between Fe and O becomes stronger，as well as the band gap is enlarged. Nevertheless，it does not cause considerable change in B’-site cation W. The process of transfer of electrons is dominated by Fe-Fe in SrKFeWO₆ compared with Fe-W charge transfer in Sr₂FeWO₆ before doping.