Monitoring of magnetism in passivated/terminated zigzag-edged triangular-shaped nanodisks

For the first time, we show a monitoring of magnetism which can be done in the nano-sized (5–15 Å) graphene nanodisks (GNDs), i.e., zigzag-edged triangular GNDs (ZET-GNDs) passivated/terminated by making mixtures of the passivating/terminating complexes. The example chosen here is a ZET-GND passivated/terminated by various mixtures of the H, 2H, and the hydroxyl OH groups. A first-principles method is used to investigate the magnetic properties which possess large magnetic moments. For 2H-passivation of ZET-GNDs, one achieves total spin values which are just double of those obtained for the mono H-passivated ones. The magnetic behavior of the ZET-GNDs passivated by OH is very much similar to that of the H-passivated ones in achieving large magnetic moments. The spin value scales with the linear dimension of the ZET-GNF which results from the topological frustration of the π bonds and the induced spin distributions in graphene structures. The maximum energy gap approaches to an asymptotic value of about 0.4 eV which may result into the occurrence of large magnetic moments in the passivated/terminated ZET-GNDs beyond the nanoscale at room temperature. The sp ₃-hybridization found at the outmost C atoms in a ZET-GND caused by termination by suitable complexes like 2H kills the π-p orbital at these C atoms and alters drastically the total magnetic moments. The graphene fragments may thus be excellent candidates for the development of several types of the spintronic devices.