Structure distortion related magnetic anisotropy in 5d transition-metal dimer adsorbed g-C3N4 monolayers

Abstract

Abstract Among the various two-dimensional (2D) materials, g-C3N4 monolayer has a novel two-dimensional sheet structure with unique characteristics and wide applications. The pristine g-C3N4 is semiconductor with an indirect-band-gap of 1.21 eV. The g-C3N4 adsorbed other materials has proven to be an effective method to change the performance of g-C3N4. Here, we investigated the adsorption energy, stable geometry, electronic structure and magnetic properties of Os, Ir atoms and its dimers adsorbed 2D g-C3N4 monolayers by first-principles calculations. We have considered several possible adsorption sites and select the center of vacancy site after the structure optimization to carry out the further calculations. The Os atom and Os–Ir dimer adsorbed g-C3N4 monolayers are n-type semiconductors, and the Ir–Os, Os–Os and Ir–Ir dimer adsorbed g-C3N4 monolayers are half-metallic. The larger magnetic anisotropy energy (MAE) in the perpendicular direction is more suitable for application than the MAE in the horizontal plane. The MAE of Os adsorbed g-C 3N4 monolayer shows a large perpendicular MAE of 5.192 mJ/m 2 at the tensile strain of 4%. The Ir–Ir adsorbed g-C 3N4 monolayer has the in-plane MAE at compressive strain of −4% and turn into perpendicular MAE of 0.275, 1.516 and 0.361 mJ/m2 at a strain of −6%, 0% and 4%, the Os and Ir–Ir dimer adsorbed g-C3N4 monolayer is promising candidates for room temperature applications. Our results reveal that 5d TM atoms and its dimers adsorbed g-C3N4 monolayers have potential applications in spintronic devices.