A Comparison of the Structural, Electronic, Mechanical and Phonon Properties of Silicene and Carbon-Substituted Silicene from First Principles

The structural, electronic and phonon properties of silicene and carbon-substituted silicene (siliphene) were investigated exploiting the density functional theory (DFT) approach. The electronegativity of the C and the Si atoms in the siliphene suggest that when the ratio of carbon:silicon is 1:1, siliphene is a semiconductor. Moreover, the electrons in the highest occupied molecular orbitals of the silicene reach the Fermi level, so it has metallic behavior with a 0.29eV Van Hove singularity. The Young's modulus and shear modulus of the siliphene are estimated to be 0.16 TP and 0.24 TP, respectively. In addition, by less than 10 eV, siliphene has fewer allowed modes of crystal vibrations than silicene.