title: Spin-polarized transport in hydrogen-passivated graphene and silicene nanoribbons with magnetic transition-metal substituents.
abstract: We present a systematic theoretical study of the electronic transport in hydrogen passivated zigzag graphene and silicene nanoribbons with between zero and four neighboring H atoms on one edge replaced by magnetic transition metals (Fe, Co, and Ni). The calculations were performed using equilibrium transport and density-functional theory with the generalized gradient approximation to exchange and correlation. We considered the magnetic moments of the two edges aligned both ferromagnetically (Ferro-F form) and antiferromagnetically (Ferro-A form). The Ferro-A graphene-based ribbons were all semiconducting and would support moderate spin-polarized currents of either sign by applying positive or negative gate voltages. The Ferro-F graphene-based ribbons were all metallic; the most interesting for possible spintronic applications being that with a single Ni atom, in which strong spin-filtering at low bias resulted from a deep trough in the transmission of one spin component around the Fermi level. By contrast, in the Si-based analog this trough was split, partially eliminating the polarization of the current. This splitting was found to be related to the buckled structure of the Si-based nanoribbon, which has its origin in its preference for sp(3)-like hybridization.
authors.affiliation: Departamento de Física, Universidad de Oviedo, E-33007 Oviedo, Spain.
authors.forename: A
authors.initials: A
authors.lastname: García-Fuente
authors.affiliation: Departamento de Física de la Materia Condensada, Facultad de Física, Universidad de Santiago de Compostela, E-15782 Santiago de Compostela, Spain.
authors.forename: L J
authors.initials: LJ
authors.lastname: Gallego
authors.affiliation: Departamento de Física Teórica, Atómica y Óptica, Universidad de Valladolid, E-47011 Valladolid, Spain. avega@fta.uva.es.
authors.forename: A
authors.initials: A
authors.lastname: Vega