Commensurate Magnetic Structures in ThCr2Si2-Type Materials: A New Symmetry-Based Classification Scheme and Prediction of Emergent Phenomena

RM

₂X₂ (R – is a rare-earth metal or K, Ca, Ba and others; M – is a 3d-, 4d-, 5d-transition metal; X – is Si, Ge, P, As and others) materials with the ThCr₂Si₂-type crystal structure exhibit a remarkable diversity of magnetic structures and phase transitions. We perform a comprehensive representational analysis of commensurate magnetic structures and propose a new classification scheme based on symmetry consideration. Our analysis demonstrates that all previously reported commensurate magnetic structures in these materials conform to this scheme. Furthermore, it allows us to suggest novel magnetic structures for unexplored RM₂X₂ compounds, identify altermagnets among them and predict several emergent phenomena in these materials such as anomalous Hall and Nernst effects and transverse piezoelectric effect.