Electronic and magnetic properties of SiC nanoribbons by F termination
College of Physics and Electronic Engineering, Nanyang Normal
2 College of Physics and Information Engineering, Henan Normal University, Xinxiang, Henan 453007, P.R. China
Received in final form: 6 October 2011
Published online: 21 November 2011
By using the first-principles calculations, the electronic properties are studied for the F-terminated SiC nanoribbons (SiCNRs) with either zigzag edges (ZSiCNRs) or armchair edges (ASiCNRs). The results show that the broader F-terminated ZSiCNRs are metallic and the edge states appear at the Fermi level, while the F-terminated ASiCNRs are always semiconductors independent of their width but the edge states do not appear due to the Si-C dimer bonds at the edges. The charge density contours analyses shows that the Si-F and Si-C bonds are all ionic bonds due to the much stronger electronegativities of the F and C atoms than that of the Si atom. However, the C-F bonds display a typical non-polar covalent bonding feature because of the electronegativity difference between the F and C atoms of 1.5 is a much smaller than that of between the F and Si atoms of 2.2, as well as the tighter bounded C 2s22p2 electrons with smaller orbital radius than the Si 3s23p2 electrons. For both the F- and the H-terminated ZSiCNRs, the ground state is a ferromagnetic semiconductor.
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag, 2011