Symmetry of valence states of heusler compounds explored by linear dichroism in Hard-x-ray photoelectron spectroscopy

This study reports on the linear dichroism in angular-resolved photoemission from the valence band of the Heusler compounds NiTi _0.9Sc_0.1Sn and NiMnSb. High-resolution photoelectron spectroscopy was performed with an excitation energy of hν=7.938keV. The linear polarization of the photons was changed using an in-vacuum diamond phase retarder. The valence band spectra exhibit the typical structure expected from first-principles calculations of the electronic structure of these compounds. Noticeable linear dichroism is found in the valence band of both materials, and this allows for a symmetry analysis of the contributing states. The differences in the spectra are found to be caused by symmetry-dependent angular asymmetry parameters, and these occur even in polycrystalline samples without preferential crystallographic orientation.