Akademik Veri Yönetim Sistemi
Physical Review Applied, cilt.25, sa.1, 2026 (SCI-Expanded, Scopus)
Two-dimensional magnetic materials are promising candidates for next-generation spintronic devices because their magnetic order can be tuned by external factors, such as strain. In this work, we study FeX4 (X=N,P) in monolayer and bilayer forms through density-functional-theory calculations combined with Monte Carlo simulations and present a comprehensive picture of their structural, electronic, and magnetic behavior under biaxial strain. With respect to the monolayer configurations, the FeN4 structure exhibits a planar geometry and semiconducting properties, whereas the FeP4 structure adopts a buckled morphology and demonstrates metallic behavior. Both ML-FeN4 and ML-FeP4 are characterized by dynamic and thermal stability. In contrast, other pnictogen-containing monolayers, including FeAs4, FeSb4, and FeBi4, display structural instability. Under applied biaxial strain, the electronic character of ML-FeP4 changes from metallic to semiconducting, while ML-FeN4 maintain their semiconducting nature. In the bilayer counterparts, interlayer interactions enhance magnetic moments and alter overall stability compared with those in the monolayers. Monte Carlo simulations reveal strain-driven magnetic phase transitions together with significant variations in transition temperatures. The Curie temperature reaches about 980 K in the ferromagnetic regime of FeN4 and around 300 K in the unstrained ferromagnetic state of FeP4. BL-FeN4 remains antiferromagnetic under strain but switches between different antiferromagnetic configurations with transition temperatures in the several-hundred-kelvin range, while BL-FeP4 exhibits a strain-induced ferromagnetic phase with a transition temperature close to 133 K. These findings demonstrate the potential of Fe-based two-dimensional systems for strain-controlled and thermally robust low-power spintronic applications.