Noncollinear magnetism in Lithium-doped zigzag graphene nanoribbons

Abstract Based on density functional theory and non-equilibrium Green’s function method, we studied noncollinear magnetism and electronic transport in zigzag graphene nanoribbon (ZGNR) doped with Li atom. Compared to pristine ZGNR, the Li-doped ZGNR presents characteristic features of magnetization distribution, which depends on the position of Li atom. When the magnetizations of two leads are parallel, i.e. θ = 0 ° , the Li atom induces an antiferromagnetic order on the edge, which is attributed to the change in exchange strength due to charge transfer. As for nonzero θ , the magnetization distribution in the case of interior adsorption shows obvious spin spiral. However, in edge adsorption, the spin spiral does not occur and a two-region feature appears. Moreover, the rotation sense of magnetization for edge adsorption becomes counter-clockwise which is different from the interior adsorption. The transmission presents distinct features for edge and interior adsorption. As θ = 180 ° , the transmission coefficient at Fermi level is about two for interior adsorption but drops to about one in edge adsorption. These results provide considerable insights into the effect of doping on noncollinear magnetism and spin transport in ZGNR.