Jesse Maassen *†, Wei Ji *†‡, and Hong Guo †
† Centre for the Physics of Materials and Department of Physics, McGill University, Montreal, Quebec H3A 2T8, Canada
DOI:10.1021/nl1031919 Publication Date: January 15, 2011
We report a first principles study of spin transport under finite bias through a graphene−ferromagnet (FM) interface, where FM = Co(111), Ni(111). The use of Co and Ni electrodes achieves spin efficiencies reaching 80% and 60%, respectively. This large spin filtering results from the materials specific interaction between graphene and the FM which destroys the linear dispersion relation of the graphene bands and leads to an opening of spin-dependent energy gaps of ≈0.4−0.5 eV at the K points. The minority spin band gap resides higher in energy than the majority spin band gap located near EF, a feature that results in large minority spin dominated currents.
Keywords: Molecular electronic devices; electron transport; graphene; NEGF-DFT