Interface effects in hybrid hBN-graphene nanoribbons

[EN] We analyze the electronic properties of a hybrid graphene-BN nanoribbon system, using a Hubbard model Hamiltonian within a mean field approximation. Due to the different electronegativities of the boron and nitrogen atoms, an electric field is induced across the zigzag graphene strip, breaking the spin degeneracy of the electronic band structure. Optimal tight-binding parameters are found from first-principles calculations. Edge potentials are proposed as corrections for the on-site energies, modeling the BN-graphene nanoribbon interfaces. We show that half-metallic responses in the hybrid systems may be driven with the help of an external electric field. We also study the role of defects across the graphene nanoribbon and at the h-BN/graphene interface regions. Modulations on the spin-dependent gaps may be achieved depending on the nature and position of the defect, constituting a way towards spin-gap engineering by means of spatial doping.This work has been partially supported by Brazilian Agencies CAPES and CNPq and Spanish MINECO under grant FIS2015-64654-P. A.L. thanks the financial support of FAPERJ under grant E-26/202.953/2016, and the INCT de Nanomateriais de carbono. C.L. thanks the financial support of CNPq. L.C. gratefully acknowledges helpful discussions with M.J. Ruiz