Interaction-mediated Co-existence of Altermagnetism and Topology

Jasmin Bedow; Nitin Kaushal; Marcel Franz

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arXiv · 2608.23442

Interaction-mediated Co-existence of Altermagnetism and Topology

Jasmin Bedow·Nitin Kaushal·Marcel Franz

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Abstract

We study an extended Hubbard model on Lieb lattice at electron filling 2 and 4, and demonstrate that the interactions lead to the simultaneous emergence of altermagnetic order and a topological gap. Using unrestricted Hartree-Fock theory, we evaluate both the altermagnetic and topological order parameters and show that they co-exist with an associated quantum spin Hall effect in a large region of the phase diagram, which we further support using exact diagonalization. Moreover, we demonstrate that inversion-symmetry breaking terms can also mediate second-order topological phases with associated corner modes.

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Jasmin Bedow, Nitin Kaushal, Marcel Franz. 2026-08-24. Interaction-mediated Co-existence of Altermagnetism and Topology. https://arxiv.org/abs/2608.23442

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