Prediction of novel two-dimensional room-temperature ferromagnetic rare-earth material - GdB₂N₂ with large perpendicular magnetic anisotropy

Two-dimensional (2D) ferromagnets with large magnetic anisotropy are promising in modern spintronics, but low Curie temperature and small magnetic anisotropy energy (MAE) hinder their applications seriously. Herein, by employing density functional theory (DFT) calculations, we predict a new kind of 2D ferromagnetic materials - GdB₂N₂, which possesses large magnetic moment (∼7.87 μB/f. u.), very high Curie temperature (∼335 K) and large perpendicular magnetic anisotropy (∼10.38 meV/f. u.). Biaxial strain ranging from −0.5% to 5% and different concentrations of charge-carrier doping (≤0.5 e/h per f. u.) are further applied to reveal the influence on the Curie temperature and MAE. The magnetic ordering of GdB₂N₂ is found dominated by a Ruderman-Kittel-Kasuya-Yosida (RKKY) mechanism. The prediction of such a novel 2D ferromagnet presented here, not only enriches the family of 2D ferromagnetic materials, but also makes it possible to combine traditional 2D materials and rare-earth metals for achieving more intriguing magnetic properties, which could eventually carve out a new path for the next-generation spintronic devices and sensors.