Investigation of atomic disorder in half metallic equiatomic quaternary Heusler alloy CoFeCrSi

In order to study the atomic disorder on electronic structure equiatomic quaternary Heusler alloy CoFeCrSi, we simulated 6 kinds of swap disorders and 12 kinds of antisite disorders. By employing first principles calculations, our work revealed that ordered CoFeCrSi could maintain a half-metallicity and total magnetic moment of 3 mu(B) when lattice constant ranges from 5.55 to 5.76 angstrom. Among various disorders, Fe-Cr swap disorder and Si(Cr) antisite disorder could form spontaneously owing to their negative formation energies. Among various swap disorders, only Co-Fe swap disordered structure can preserve half metallicity, and spin polarization higher than 95% also can exist in Co-Si, Cr-Si and Fe-Cr swap disordered structures. Besides, spin down energy gap can be preserved in all antisite disorders except Co(Cr), Co(Si) and Fe(Si). Therefore, CoFeCrSi possesses robust half-metallicity.