Altermagnetism; discovering a new magnetic phase

EPFL, Lausanne

Altermagnets are a new classification in the family of magnetic materials where the spin symmetries are characterised by rotations rather than translation or inversion. This seemingly small distinction has far reaching consequences which are most clearly expressed in the lifting of the spin degeneracy in reciprocal space. Using a combination of bulk sensitive soft X-ray photoemission spectroscopy (ARPES) and spin-resolved ARPES in the UV range we have been the first to directly resolve this spin splitting and distinguish it from the influence of spin-orbit interaction [1]. Besides discussion these results and more recent progress, I will also focus on what lead to the discovery and how it altermagnetism is truly different from anything we have studied before. It will be contrasted to other forms of non-collinear magnetism and I will indicate some of the routes that this field might take in the near future.

1. J. Krempasky et al. Nature 626, 517 (2024)