3rd rank tensorial response in altermagnets

There is an increasing need for macroscopic tools to probe the symmetries of altermagnetic materials, and to distinguish them from antiferromagnets. In this talk, we present a systematic classification of all 3rd rank response tensors in crystalline materials using group representation theory. Applying these ideas on time-reversal odd response in altermagnetic materials, we find that there are unique macroscopic observables, including piezomagnetism, that can be used to elucidate the distinct symmetry of altermagnetic order parameters.