Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

MA: Fachverband Magnetismus

MA 5: Surface Magnetism and Topological Insulators (joint session MA/TT)

MA 5.2: Vortrag

Montag, 9. März 2026, 09:45–10:00, POT/0351

Exchange splitting at surfaces: a new paradigm for spin-polarization in antiferromagnets — •William Schaarman and Sophie Weber — Chalmers University of Technology, Göteborg, Sweden

There has been recent interest in combining the robustness and ultrafast dynamics of antiferromagnets with the transport properties of spin-polarized band structures. While antiferromagnetic bands are typically spin-degenerate, exceptions to this rule such as the altermagnets have demonstrated the possibility to obtain spin polarization in bulk antiferromagnets via selective symmetry lowering. Here, we use symmetry analysis and density functional theory to examine a ferromagnetic-like exchange splitting at certain surfaces. Such spin polarization of the surface-projected band structure can occur for surface orientations with a net two-dimensional magnetization which can emerge via symmetry-lowering at the antiferromagnet's surface. By analyzing the band structure of a slab geometry projected onto a single surface, we confirm surface spin polarization in two representative materials, magnetoelectric Cr2O3 and altermagnetic FeF2. We rationalize the magnitudes of exchange splitting on distance surface orientations in these two materials as a complex interplay between the exchange and crystal field splittings of individual magnetic atoms making up the surface. Notably, our analysis shows the effect of surface exchange splitting can in some cases be of the order of eV which has important implications for spintronic devices.

Keywords: Exchange splitting; Surface magnetism; Spin polarization; Antiferromagnet; Crystal field splitting