Monolayer MX2 (M = Cr, Mn; X = Se, Te) with a square lattice: A ferromagnetic half-metal with high Curie temperature

Ferromagnetic half-metal materials are regarded as important materials for the spintronic devices because of the fully spin-polarized carrier transport. Here, the new two-dimensional (2D) magnetic material MX2 (M = Cr, Mn; X = Se, Te) with the square lattice is designed and studied by first-principle calculations. Molecular dynamics simulation, mechanical parameters, and phonon spectrum are used to confirm structural stability. The study found that MX2 is a ferromagnetic (FM) half-metal material with a large spin and a half-metallic gap. Based on the Heisenberg model, it was discovered that MX2 has Curie temperature well above room temperature, and the fully spin-polarized transport properties in MX2 nano-devices are ensured through the volt-ampere characteristic curves. In addition, the study found that the biaxial tensile strain has significant improvement effects on ferromagnetism. The present work develops FM half-metal materials MX2 with excellent performance, which has enormous application potential in spintronics.