Electronic structures of zigzag SiC nanoribbons with asymmetric hydrogen-terminations

Using hybrid density functional calculations, we investigate the electronic properties of zigzag SiC nanoribbons (ZSiCNRs) with different hydrogen-terminations. We find that the asymmetric hydrogen-terminations can break the magnetic degeneracy and favor ferromagnetic state in the ZSiCNRs. The nanoribbons are transformed to half-metals by the bare Si edge, while the saturated Si/C edge brings quasi-half-metallic behaviors, for which two spin-polarized bands intersect at the Fermi level with tiny band gaps. The opening of such tiny gaps depends on the molecular origins of bands, as well as ribbon widths. For wide nanoribbons, all the ZSiCNRs with asymmetric hydrogen-terminations are converted to half-metals. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4732786]