Talk by Matteo Dürrnagel

Exotic ordering mechanisms from non-symmorphic momentum space symmetries.

Abstract:

In this talk I will promote systems with projective symmetry representations as promising platforms for novel quantum many body phases. The projective factor system in real space can give rise to a non-symmorphic space group representation in momentum space with direct consequences for the symmetry allowed ordering tendencies of the system. I will exemplify their potential on two recent examples - extended s-wave altermagnetism [1] and nodeless pair density wave order [2] - and discuss both their microscopic formation mechanisms as well as experimentally traceable signatures.

Finally, I will highlight the relevance of our results for newly synthesized M-point twisted moiré materials and magnetic systems hosting emergent projective symmetry representations in their effective low energy description.

[1] M. Dürrnagel, L. Klebl, T. Müller, R. Thomale, and M. Klett, Extended s-wave altermagnets, arXiv 2508.20163 (2025)
[2] M. Dürrnagel, C. A. Baum, M. Klett, L. Klebl, and R. Thomale, Pair density wave order from non-symmorphic momentum symmetry, arXiv 2609.05603 (2026)

Host:

Brian Møller Andersen