Investigation of half-metallicity and magnetism of bulk and (111)-surfaces of Fe2MnP full Heusler alloy

Abstract

The structural, electronic, magnetic, elastic and phonon properties of bulk and electronic and magnetic properties of (111)-surfaces of AlCu2Mn-type Fe2MnP Heusler alloy have been investigated by using density functional theory based on the generalized gradient approximation scheme. The cohesive energy confirmed the stability of the alloy considered at an equilibrium lattice constant of 5.5628 Å. We observed a half-metallic nature in the bulk alloy with energy band gaps of 0.34 eV and spin-flip gaps of 0.09 eV with 100% spin-polarization in the minority spin electrons. The computed magnetic moments for the Fe2MnP alloy are found to be 4 μB/f.u. The investigated elastic constants, phonon dispersion and density phonon states showed that the Fe2MnP alloy is mechanically and dynamically stable. We also found that the alloy is ductile from the Poisson's and B/G ratios. The half-metallic ferromagnetic nature is preserved in the P (111)-terminated slab among all terminations with 100% spin-polarization which is a crucial property of spin devices, since it can be optimize their performance. The spin-polarization clearly decreases by nearly 75% for Fe (111) and Mn (111)-terminated slabs due to surface states located below the Fermi level. Moreover, the computed atomic magnetic moments of (111)-slabs of the Fe2MnP Heusler alloy are extremely close to the atomic bulk values.