第一性原理研究具有原子无序的Co_2FeSi合金的电子结构、磁性与半金属特性(英文)

Electronic Structures,Magnetism,and Half-metallicity of Disordered Co_2FeSi Alloy:A First-principles Study

应用全势线性缀加平面波方法,并结合GGA＋U方案,研究了原子无序性对full-Heusler合金Co2FeSi的电子性质和磁性质的影响.在full-Heusler合金Co2FeSi中,本文考虑了Co-Fe,Co-Si和Fe-Si 3种类型的原子无序.通过研究发现Fe-Si原子无序体系的总能量在3种原子无序当中最低,并且在U15~U20的范围内,Fe-Si原子无序体系依然保持半金属特性;另外,Co-Fe原子无序和Co-Si原子无序体系具有较高的总能量,这2种原子无序对体系的电子性质和磁性质产生了很大的影响,并且完全破坏了Co2FeSi的半金属特性.

The effect of atomic disorders on the electronic and magnetic properties of the full-Heusler compound Co2FeSi is investigated by means of the full-potential linearized augmented plane wave method within the GGA＋U.We considered three types of atomic disorder,i.e.,the Co-Fe disorder,the Co-Si disorder and the Fe-Si disorder in the full-Heusler compound Co2FeSi.We found that the Fe-Si disorder has the lowest total energy among the three types of atomic disorder and retains the half-metallic character in the range of U15-U20.On the other hand,the Co-Fe disorder and the Co-Si disorder have the higher total energy and the half-metallic character was destroyed by the disorders.