Effect of local atomic disorder on the half-metallicity of full-Heusler Co₂FeSi alloy: a first-principles study

This paper investigates the effect of atomic disorder on the electronic structure, magnetism, and half-metallicity of full-Heusler Co₂FeSi alloy by using the full-potential linearized augmented plane wave method within the generalized gradient approximation (GGA) and GGA+U schemes. It considers three types of atomic disorders in Co₂FeSi alloy: the Co–Fe, Co–Si, and Fe–Si disorders. Total energy calculations show that of the three types of disorders, the Fe–Si disorder is more likely to occur. It finds that for the Co–Si disorder, additional states appear in the minority band-gap at the E_F and the half-metallcity is substantially destroyed, regardless of the disorder level. On the other hand, the Co–Fe and Fe–Si disorders have little effect on the half-metallicity at a low disorder level. When increasing the disorder levels, the half-metallcity is destroyed at about 9% of the Co–Fe disorder level, while that stays at 25% of the Fe–Si disorder level.