122型铁基超导材料晶体结构探析

Study on crystal structure of 122-type Fe-based superconductor

基于第一性原理的密度泛函理论(DFT),采用全势线性增强平面波结合改进的局域轨道方法(APW+lo)和一般梯度近似(GGA),对122型铁基超导体系的AeT2Pn2化合的结构、能量、磁矩、电子能带和电子态密度进行了计算和分析.研究AeT2Pn2体系的超导温度同晶格中的键长,键角,磁性,电子能带和电子态密度之间的关系,从这类体系的晶格结构层面给出了对提高超导温度有利的几个因素.结果表明,相对于122型的其他体系具体而言,BaFe2As2系列材料的超导温度相对较高.

Based on the density functional theory,using full -potential linearized augmented plane wave and improved local orbital and GGA method,the structures,energies,magnetism,electronic bands,and densities of states of the superconductivity 122 type AeT2 Pn2 compounds were calculated and analyzed.The superconducting transition temperature （TC ） of AeT2 Pn2 was analyzed with the bond lengths,bond angles, magnetism,electronic bands,and densities of states. The favorable factors to heighten TC for 122-type Fe-based superconductor was given. The results showed that [Fe2 As2 ]black series have the strongest spin -polarized magnetism,most stable antiferromagnetic structure,obvious splitting of spin -up and down bands at Fermi level,and canonical tetrahedral FeAs4 ,and the TC relatively higher than [Ni2 As2 ]and [Fe2 P2 ]series.