Transition from antiferromagnets to altermagnets: Symmetry-breaking theory

Considering the similar real-space configurations of opposite-spin sublattices in antiferromagnets (AFMs) and altermagnets (AMs), the authors establish here a symmetry-based framework for connecting between AFMs and AMs via spin groups. They find that symmetry breaking of combined inversion or translation with time-reversal symmetry will drive AFM-to-AM phase transitions. The authors not only establish a theoretical framework for the transition but also provide practical approaches utilizing the AFMs achievements for 100 years to obtain AMs, significantly expanding the scope of AM materials for both theoretical studies and future practical applications.