Magnetic Properties of Single Transition-Metal Atom Absorbed Graphdiyne and Graphyne Sheet from DFT plus U Calculations

The electronic and magnetic properties of single 3d transition-metal (TM) atom (V, Cr, Mn, Fe, Co, and Ni) adsorbed graphdiyne (GDY) and graphyne (GY) are systematically studied using density functional theory (DFT). It is found that the electronic structures of TM-GDY/GY are sensitive to the value of the on-site Coulomb energy for the TM 3d orbital. It is crucial to use DFT+U method and accurately account for the electron correlation in the calculations. By using linear response method, we are able to determine the U-eff value for all TM adatom. We find that the adsorption of TM atom not only efficiently modulates the electronic structures of GDY/GY system but also introduces excellent magnetic properties, such as spin-polarized half-semiconductor. Such modulation originates from the charge transfer between TM adatom and GDY/GY sheet as well as the electron redistribution of the TM intra-atomic s, p, and d orbitals. Our results indicate that the TM adsorbed GDY/GY are excellent candidates for spintronics.