Ab Initio Study of the Magnetism and Half-Metallic Properties of d0 Quaternary Heusler Alloys BaNYO (Y = K, Rb, and Cs)

Abstract

An ab initio theory has been applied to investigate the electronic, elastic, magnetic, and half-metallic behaviors of the newly designed quaternary Heusler compounds BaNYO (Y = K, Rb, and Cs) without 3d transition metal elements. However, elastic properties show that our compounds are ductile and anisotropic. The calculated results show that our compounds are half-metallic with an integer magnetic moment of 2.00μB at the equilibrium lattice parameter, with 100% spin polarization around the Fermi level, which follows the famous Slater–Pauling rule, Mtot = 16 − Zt, Mtot, is the total magnetic moment and Zt is the total number of valence electrons. Based on its equilibrium and strained lattice constants, the magnetic and half-metallic behaviors of this compound have been discussed in detail. Large half-metallic gaps of BaNYO (Y = K, Rb, and Cs) compounds of 0.95, 0.90, and 0.85 eV, respectively, have been found in our work, which is nearly larger than any previous study. Furthermore, the calculated negative formation energy and cohesive energy indicate that these two alloys have good chemical stability. This theoretical investigation provides further insight into the application of BaNYO compounds as spintronic materials.