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MA: Fachverband Magnetismus

MA 21: Phd Focus Session: Altermagnets: Foundations and Experimental Evidence

MA 21.8: Invited Talk

Wednesday, March 20, 2024, 12:15–12:45, H 1058

Negative critical current in an altermagnet Josephson junction — •Carlo Beenakker — Instituut-Lorentz, Leiden University, The Netherlands

Altermagnets (metals with a d-wave magnetization that alternates direction in momentum space) differ from ferromagnets and antiferromagnets in that they combine a spin-polarized Fermi surface with a vanishing net magnetization. This unusual combination radically modifies the flow of a supercurrent in a junction where an altermagnet connects two superconductors (Josephson junction). The sign of the supercurrent oscillates as a function of the length of the junction, because of a spin-polarisation of the bound states in the junction (Andreev levels): Spin-up and spin-down levels are phase-shifted in opposite directions.

Keywords: altermagnet; Josephson junction; Andreev level