Spin-polarized electronic/transport properties of iron-benzene complex-adsorbed graphene sheets

The electronic and transport properties of a series of covalently functionalized graphene sheets m(FeBz)n-G (m, n = 1, 2) are calculated by density functional theory (DFT) and the nonequilibrium Green's function (NEGF) methods. All the studied systems are chemically stable due to the d-& pi; interaction between Fe and graphene. Addition of (FeBz)n (n = 1, 2) introduces a half-metallic behavior: the up-spin state degradates into a semiconductor channel while the down-spin state behaves as a metallic channel. Particularly, two-fold anisotropy magnetism could be obtained, with the ferromagnetic ordering extending either parallel to the graphene plane originated from the Fe -d up-spin state or perpendicular due to the d-electron coupling along the Fe-Bz-Fe-Bz chain in the down-spin state. Because of the trapping effect, attaching (FeBz)n decreases the conductivity. Anisotropy inherited from graphene after functionalized with (FeBz)n (n = 1, 2): zigzag direction has higher conductivity than armchair direction. The number and alignment style of (FeBz)n (n = 1, 2), and the spin polarized character, all have impacts on the transport property. Our findings provide useful guidelines for achieving graphene-based electronic and spintronic nanodevices by attaching other similar long multi-decker metal-arene systems.