Two-dimensional ferromagnetic penta-FeP2 with high Curie temperature and carrier mobility

In this work, we investigated the stability, electronic structures, and magnetic properties of a 2D pentagonal iron phosphide (penta-FeP₂) through density functional theory (DFT) calculations. The predicted penta-FeP₂ is an FM semiconductor with thermal, dynamical, and mechanical stability, and narrow direct band gap of 0.916 eV. The estimated T_C surpasses 705 K, which is sufficiently higher than room temperature. The MAE is as high as 358 μeV/Fe, which enhances the FM stability of the penta-FeP₂. In addition, the 2D material also exhibits ultrahigh mobility for both holes and electrons. The light electron mobility is up to 21, 992 cm² V⁻¹ s⁻¹, while the light hole mobility is 2, 890 cm² V⁻¹ s⁻¹. It also exhibits isotropic visible light absorption and a low lattice thermal conductivity of ∼20 W m⁻¹ K⁻¹ at room temperature. The 2D FeP₂ displays a number of desirable properties, including excellent stability, high T_C, large MAE, high carrier mobility, and a direct band gap. These characteristics make it a promising candidate for spintronic devices.