THEORETICAL AND EXPERIMENTAL-STUDY OF THE ELECTRONIC-STRUCTURE OF PTMNSB

The electronic structure of PtMnSb has been studied by means of the linear muffin-tin-orbital method of band-structure calculation. In agreement with earlier investigations a so-called half-metallic behavior has been found. Until now, this exotic feature of the band structure of PtMnSb, which is made responsible by some authors for its high Kerr rotation, could not clearly be confirmed by experiment. Using the Korringa-Kohn-Rostoker band-structure technique it could be shown that lattice imperfections, which can never be completely suppressed in this system, have a dramatic impact on the spin polarization in the vicinity of the Fermi level. This explains why photoemission experiments could find only a degree of photoelectron polarization at the threshold noticeable below the ideal value of 100%. To get further insight into these problems, x-ray-absorption measurements using circularly polarized radiation have been performed at the L2,3 edges of Pt, the K edge of Mn, and the L1 edge of Sb. The results of these experiments, which give in a component-resolved way a rather direct access to the spin polarization for the unoccupied part of the conduction band, are found in reasonable agreement with theoretical data.