sp2-like hybridization of silicon valence orbitals in silicene nanoribbons

Silicene nanoribbons grown on a silver (110) substrate have been studied by reflection electron energy loss spectroscopy as a function of the electron beam incidence angle alpha. The spectra, taken at the Si K absorption edge (1.840 keV), reveal the presence of two distinct loss structures attributed to transitions 1s ->pi* and 1s ->sigma*, according to their intensity dependence on alpha. Such behavior, when compared to graphite, attests the sp(2)-like hybridization of the silicon valence orbitals in the silicene nanoribbons as is, indeed, for carbon atomic bonds of graphene. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3557073]