Electronic structure, magnetism and disorder effect in double half-Heusler alloy Mn2FeCoSi2

Abstract

• A new type of double half Heusler alloy Mn 2 FeCoSi 2 is designed. • The study of phonon diffusion and molecular dynamics proves its dynamic stability. • Half metallicity can be preserved when c / a ranges from 1.8 to 2.2. • The Mn 2 FeCoSi 2 possesses a robust half-metallicity against the atomic disorder. The electronic structure and magnetism of a new type of half-Heusler alloy, i.e., double half-Heusler (DHH) alloy Mn 2 FeCoSi 2 are investigated. Our calculations reveal that Mn 2 FeCoSi 2 is a ferrimagnet with a magnetic moment of 3 μ B , it has a stable magnetism and its half metallicity can be preserved when c/a ranges from 1.8 to 2.2. Furthermore, 6 kinds of swap disorders and 12 kinds of antisite disorders are simulated to study the influence of atomic disorder on half metallicity of Mn 2 FeCoSi 2 . Half metallicity is maintained in Co-Fe disordered structure and spin polarization of Mn-Si, Mn-Fe and Si-Co disordered structure also reaches up to 94%, 98% and 97%, respectively. With regard to various antisite disorders, 100% spin polarization could be preserved in Co(Fe), Fe(Co), Fe(Mn), Mn(Co), Mn(Fe) and Si(Co) disordered structures. Therefore, Mn 2 FeCoSi 2 possesses a robust half-metallicity against the atomic disorder.