Half-metallicity of the inverse Heusler alloy Mn2CoAl(0 0 1) surface: A first-principles study

Abstract

Half-metals exhibit 100% spin polarization at the Fermi level. Thus, they are promising magnetic electrode candidates in spintronics. We investigated the electronic structures, magnetism, and half-metallicity of the inverse Heusler alloy Mn2CoAl(001) surface by the all-electron full-potential linearized augmented plane-wave method within the generalized gradient approximation. Two types of surface terminations were considered, namely, the AlMn terminated (AlMn-term) and CoMn terminated (CoMn-term) surfaces. From the calculated layer-projected density of states, we found that the half-metallicity was preserved on the surface of the AlMn-term. However, the width of the minority-spin gap was significantly reduced because of the surface states located just above the Fermi level. By contrast, the CoMn-term lost its half-metallicity because of the strong surface potential effect on the surface Co atom. The magnetic moments of Mn atoms on the surfaces of both terminations are considerably increased compared with those in the deep inner layers, while that of the surface Co atom on the CoMn-term is slightly increased.