Thursday, April 25, 2013

1304.6665 (Simone Marocchi et al.)

Graphene-mediated exchange coupling between cobaltocene and magnetic
substrates
   [PDF]

Simone Marocchi, Paolo Ferriani, Nuala Mai Caffrey, Franca Manghi, Stefan Heinze, Valerio Bellini
Using first-principles calculations we demonstrate sizable exchange coupling between a magnetic molecule and a magnetic substrate via a graphene layer. As a model system we consider cobaltocene (CoCp$_2$) adsorbed on graphene deposited on Ni(111). We find that the magnetic coupling between the molecule and the substrate is antiferromagnetic and varies considerably depending on the molecule structure, the adsorption geometry, and the stacking of graphene on Ni(111). We show how this coupling can be tuned by intercalating a magnetic monolayer, e.g. Fe or Co, between graphene and Ni(111). We identify the leading mechanism responsible for the coupling to be the spatial and energy matching of the frontier orbitals of CoCp$_2$ and graphene close to the Fermi level, and we demonstrate the role of graphene as an electronic decoupling layer, yet allowing spin communication between molecule and substrate.
View original: http://arxiv.org/abs/1304.6665

No comments:

Post a Comment