Resonant-photoemission investigation of the Heusler alloys Ni₂MnSb and NiMnSb

Photoemission was used to investigate the electronic density of states (DOS) in Ni₂MnSb and NiMnSb. Comparisons with calculated band structures reveal reasonable agreement, but there are indications that the calculations overemphasize Ni 3d contributions at some binding energies. Resonant effects at the Mn 3p core threshold were employed to obtain information on the Mn 3d partial densities of states and these indicate that Mn 3d character is spread throughout the valence bands, in agreement with theory. These effects are strongest in the bottom of the valence band around a binding energy of 3.1 eV and produce structure which agrees well with the theoretical Mn 3d DOS, but are weak for other portions of the calculated Mn DOS. These results are discussed in the context of models for the formation of localized moments in these materials.