Transition metal driven altermagnetism and spin–orbit coupling effect in tetragonal Ce-based pnictides: a first-principles investigation

Abstract

We present a first-principles density functional theory (DFT) investigation of the structural, electronic and magnetic properties of the tetragonal CeX₂Y₂ (X = Co, Ni, and Fe; Y = P, As, and Sb) compounds, crystallizing in the ThCr₂Si₂-type structure (space group I4/mmm). Electronic properties of the relaxed structure are analyzed, highlighting the influence of Ce-4f and Co-3d states on the magnetic behaviour. The studies reveal that the Fe and Ni based compounds exhibit weak magnetism, and the Co-based compounds follow interlayer antiferromagnetic behaviour. The calculated density of states reveals a significant contribution from Ce-4f and Co-3d orbitals near the Fermi level (E_F), indicating a complex interplay between localized and itinerant electronic states. The results further suggest the potential realization of altermagnetism arising from the magnetic structure of the CeCo₂P₂, showing d-wave like band splitting in the band structure and four lobe structure in the Fermi surface picture. Inclusion of spin–orbit coupling (SOC) leads to noticeable band splitting and modification of the near-Fermi-level band dispersion, which is relevant for understanding relativistic effects in Ce-based intermetallic compounds. These results provide a reliable computational baseline for further investigations of magnetism and possible topological features in CeX₂Y₂ and related materials. The present study serves as a starting point toward exploring correlation-driven and spin–orbit–induced phenomena in Ce-based pnictides.