Prediction of high-temperature ferromagnetic semiconductors in tetrahedral superlattices

Ferromagnetic (FM) semiconductors combine the advantages of semiconductors (e.g., logic devices) and magnetic materials (e.g., memories) and have garnered increasing amounts of attention for more than half a century. However, the development of FM semiconductors faces challenges due to the scarcity of suitable candidates and their low Curie temperature. Traditionally, ferromagnetism is observed in transition metal compounds with octahedral coordination. In contrast, tetrahedral coordination compounds, with smaller crystal field splitting and weaker antiferromagnetic (AFM) direct exchange, hold promise as potential candidates for high-temperature ferromagnets but remain largely unexplored. In this work, we propose that high-temperature FM semiconductors can be realized in tetrahedral coordination superlattices (SLs). On the basis of first-principles calculations, we systematically investigated a series of MX/TMX (MX denotes group 12–16, 13–15 or 14–14 tetrahedral semiconductors, TM denotes a 3d transition metal, X denotes the ligand) SL. Among them, SiC/CrC SL emerges as a stable FM semiconductor with an indirect band gap of 0.363 eV and a high Curie temperature (TC) of ∼935 K. Furthermore, the distributions of the Cr atomic layer and interlayer magnetic couplings are explored. A uniaxial-pressure-induced AFM-to-FM phase transition is predicted. These discoveries present novel opportunities for realizing high-temperature FM semiconductors in tetrahedral coordination SLs, offering potential advancements in future spintronic applications.