Ferromagnetism and controllable half-metallicity of two-dimensional hexagonal CrOX (X = F, Cl, Br) monolayers

Searching for low-dimensional materials with high Curie temperature and full spin–polarization ratio is an urgent demand for the rapidly evolving spintronic industry. Here, the stability, electronic structures, and magnetic properties of two-dimensional hexagonal CrOX (X = F, Cl, Br) monolayers were investigated with density functional theory. The CrOF and CrOCl monolayers exhibit good stability and are ferromagnetic semiconductors with a Curie temperature of ~ 215 and 64 K, respectively, as determined from Monte Carlo simulations. High-temperature ferromagnetism and controllable half-metallicity can be realized by hole doping from a gate voltage. At a doping concentration of 0.1|e|per unit cell, the Curie temperatures of CrOF and CrOCl are increased to 385 and 576 K, respectively, and the doped systems change from semiconductors into half-metals. These findings suggest a route for controlling and tuning the electronic and magnetic properties of CrOX monolayers, which are promising materials for spintronic devices.