Dresden 2026 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 33: Altermagnets IV

MA 33.9: Vortrag

Mittwoch, 11. März 2026, 17:15–17:30, HSZ/0002

Optically tunable spin transport in bilayer altermagnetic Mott insulators — Niklas Sicheler¹, Roberto Raimondi², Giorgio Sangiovanni¹, and •Lorenzo Del Re¹ — ¹Würzburg University — ²Roma Tre

Altermagnets are a class of materials in which antiferromagnetic order coexists with non-relativistic spin splitting (NRSS), offering a promising route to spintronic functionalities without relying on strong spin*orbit coupling. In this work, we study a two-dimensional bilayer Mott insulator that realizes an altermagnetic phase shaped by the interplay between spin and layer degrees of freedom. This coupling produces a rich symmetry-breaking structure in which magnetic order is intertwined with inter-layer excitonic correlations. The layer polarization*tunable through an external gate voltage*acts as a key control parameter for this excitonic altermagnetic state. We demonstrate that an in-plane electric field applied with opposite signs across the layers generates a polarization current, which in turn drives a spin current within each layer. While the polarization current itself is isotropic, the induced spin current is highly anisotropic and can be reversed by tuning the photon energy. These results identify a mechanism for electrically and optically manipulating spin transport in correlated altermagnets, and highlight the central role of excitons in enabling controllable spin responses.

Keywords: Strongly correlated electron systems; Magnons; Excitons; Bilayers; spin waves