First principles study about Fe adsorption on planar SiC nanostructures: Monolayer and nanoribbon

Spin polarized density functional theory (SP-DFT) has been used to investigate the stability and electronic properties of Fe adsorption on SiC, both monolayer and nanoribbon (NR). For the monolayer, we obtain a magnetic moment of 2 μB (6 μB) when an Fe atom (dimer) is adsorbed on top of a hexagon. The Fe adsorption gives rise to new electronic levels inside the band gap. Fe atoms and dimers are preferentially adsorbed on top of the hexagon center of the NR, which is localized at the border of the NR. Afterwards, new electronic properties of Fe absorption are observed for the NR. For an isolated Fe atom to be adsorbed the system must be semiconductor with different band gaps for the two spin channels; however, for an Fe dimer to be adsorbed, we must obtain a spin gapless semiconductor (SGS). When the two borders of the SiC nanoribbon are equally drawn with Fe atoms, two magnetic states are obtained, which is dependent upon the edge coupling. The ferromagnetic (FM) is the most stable state and half-metallic properties are shown while for the antiferromagnetic (AFM) a narrow band gap semiconductor is obtained.

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