A novel 2D intrinsic metal-free ferromagnetic semiconductor Si₃C₈ monolayer

Metal-free magnets, a special kind of ferromagnetic (FM) material, have evolved into an important branch of magnetic materials for spintronic applications. We herein propose a silicon carbide (Si₃C₈) monolayer and investigate its geometric, electronic, and magnetic properties by using first-principles calculations. The thermal and dynamical stability of the Si₃C₈ monolayer was confirmed by ab initio molecular dynamics and phonon dispersion simulations. Our results show that the Si₃C₈ monolayer is a FM semiconductor with a band gap of 1.76 eV in the spin-down channel and a Curie temperature of 22 K. We demonstrate that the intrinsic magnetism of the Si₃C₈ monolayer is derived from p_z orbitals of C atoms via superexchange interactions. Furthermore, the half-metallic state in the FM Si₃C₈ monolayer can be induced by electron doping. Our work not only illustrates that carrier doping could manipulate the magnetic states of the FM Si₃C₈ monolayer but also provides an idea to design two-dimensional metal-free magnetic materials for spintronic applications.