Electronic structure of the Cu₂MnAl Heusler alloy

The electronic structure and chemical bonding mechanism of the Heusler alloy Cu2 MnAl are studied on the basis of band-structure calculations, using the full-potential linearized augmented-plane-wave (FLAPW) method. The calculations are performed within both the local spin-density approximation (LSDA) and the generalized gradient approximation (GGA). The calculated band structures and the densities of states within the GGA are compared with the earlier-reported experimental results of ultraviolet photoemission spectroscopy. The comparisons support the physical picture proposed by Kübler and co-workers, in which the occupied d states of Mn are delocalized by their strong interaction with the d states of Cu. The magnetic Compton profiles (MCPs) are also calculated and compared with the earlier-reported experimental results. The comparisons show that the GGA is better able to reproduce the experimental profiles than the LSDA. The spin moment on the Mn site is calculated to be 3.20 µB , which is in agreement with the value deduced from the experimental profiles.