High-efficiency spin-filtering and magnetoresistance effects in supramolecular spin valves

By using nonequilibrium Green's functions in combination with the density functional theory, we investigate the transport properties of the supramolecular spin valves made of ferrocene and pristine (p-type or n-type) graphene nanoribbons. The results show that ferrocene adsorption on pristine graphene nanoribbons gives rise to perfect magnetoresistive effect. While for ferrocene adsorption on p-type graphene nanoribbons, the perfect magnetoresistive effect disappears but a high-efficiency spin-filtering effect can be observed. More interestingly, the ferrocene adsorption on n-type graphene nanoribbons bring about the disappearance of spin polarization effect, and thus spin-filtering and magnetoresistive effect cannot be observed. Our researches also confirm that the doping type of graphene nanoribbons is a key factor for obtaining a high-performance supramolecular spintronic device.