Berlin 2024 – scientific programme
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MA: Fachverband Magnetismus
MA 19: Surface Magnetism
MA 19.4: Talk
Tuesday, March 19, 2024, 10:15–10:30, EB 407
Exchange engineering of a two-dimensional half-metal — •Xin Liang Tan1,2, Arthur Ernst3, Kenta Hagiwara1, Ying-Jiun Chen1,2, Claus M. Schneider1,2, and Christian Tusche1,2 — 1Forschungszentrum Jülich, Peter Grünberg Institut, Jülich — 2Fakultät für Physik, Universität Duisburg-Essen, Duisburg — 3Institut für Theoretische Physik, Johannes Kepler Universität, A 4040 Linz, Austria
Ideal half-metals, showing conductivity only in one spin channel, would open the way to efficient spin-injection devices for spintronics. Prototypical examples of half-metals, such as Heusler alloys and complex oxides, lose their high spin polarization at the surface or when reduced to sub-nm thickness, complicating the realization of nanoscale spintronics. Here we present a bottom-up optimization pathway for the realization of a two-dimensional(2D) itinerant half-metallic iron-palladium film via direct band structure engineering. Spin-resolved momentum microscopy enables 2D spin-resolved mapping of the full Brillouin zone. A fully polarized Fermi surface, the hallmark of a half metal, was engineered via direct control of the film-film composition and alloying. The balancing acts between the exchange interaction and the spin-orbit coupling in the 2D film allow the direct tuning of electronic states. We highlight the local critical regions in momentum space contributing to the opening up of a spin gap. Layer- and spin-resolved Korringa-Kohn-Rostoker calculations with coherent potential approximation corroborate our experimental findings and reveal the interplay between the exchange and spin-orbit interactions.
Keywords: 2D half-metal; 2D ferromagnetism; Band structure engineering; Magnetic thin-film; Itinerant hybrid magnet