Prediction of low-Z collinear and noncollinear antiferromagnetic compounds having momentum-dependent spin splitting even without spin-orbit coupling

Antiferromagnetic order offers a non-relativistic route to create spin splitting and spin polarization effects that do not rely on heavy element compounds (with strong spin-orbit coupling, SOC), and could exist even in centrosymmetric crystals. Cases enabling such non-relativistic, SOC-unrelated spin polarization effect are classified as SST-4 (SST-4A and SST-4B) of all seven possible spin splitting prototypes derived in this paper based on magnetic symmetry analysis. The authors uncovered 422 magnetic space groups (160 centrosymmetric and 262 non-centrosymmetric) and 201 candidate antiferromagnets that belong to the SST-4 category. DFT calculations for collinear and noncollinear cases are provided as basis for guiding future experiments.