Interface potentials on h-BN/graphene nanoribbons

Zigzag graphene nanoribbons (ZGNRs) present a half-metallic response for an external electric field's critical value[1], with possibilities for spin-filter applications. On the other hand, embedded ZGNRs in zigzag hexagonal boron nitride (ZBNR) exhibit half-metallicity without the presence of an external field[2]. In this work, we analyze electronic properties of a mixed nanoribbon system (ZBNR/ZGNR/ZBNR), using a Hubbard model Hamiltonian within a mean field approximation. Due to different electronegativities of boron and nitrogen atoms, an electric field is induced across the ZGNR and we found a spin-dependent band structure. Optimal tight-binding parameters are found in a tentative to retrieve DFT results for the electronic bands. Here, we are interested on gap engineering and improving the robustness of the half-metallic response of the mixed system by means of fold-like strain and other imperfections such as impurities. We consider edge potentials[3] and take into account the effects of the BN/graphene interfaces to reproduce DFT results.
[1] Y.Son, M.Cohen, and S.Louie, Nature 444 (2006)
[2] S. Bgowmick, A. K. Singh, and B. I.Yakobson, J. Phys. Chem. C 115 (2011)
[3] F. Zheng, K. Sasaki, R. Saito, W. Duan and B. Gu, J. Phys. Soc. Jpn. 78 (2009)