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MA: Fachverband Magnetismus

MA 50: Spincaloric Transport (jointly with TT)

MA 50.9: Vortrag

Donnerstag, 23. März 2017, 11:45–12:00, HSZ 403

Insights into the spin-orbit coupling mediated thermoelectric properties of half metallic full Heusler alloys — •Voicu Popescu and Peter Kratzer — Faculty of Physics and CENIDE, University Duisburg-Essen, 47057 Duisburg, Germany

We have performed first-principles investigations on the native defects in the half-metallic ferromagnetic full Heusler alloys Co₂TiZ (Z one of the group IV elements Si, Ge, Sn). We modelled the defects as dilute alloys, and treated them in the coherent potential approximation within the framework of the full potential spin-polarized relativistic Korringa-Kohn-Rostoker Green function method. The self-consistent potentials determined this way were used to calculate the residual resistivity via the Kubo-Greenwood formula and, based on its energy dependence, the Seebeck coefficient of the systems. The latter is shown to depend significantly on the type of defect, variations that are related to subtle changes in the electronic structure around the half-metallic gap induced by the spin-orbit coupling. Amongst the different investigated intrinsic defects, two of them exhibit a negative Seebeck coefficient, in good agreement with the available experimental data.