Silicon-carbide nanostructures to nanotubes

A set of novel silicon carbon nanostructures (Si2nCn) in tubular form is presented which can be extended to form silicon carbide nanotubes with variable diameters. The generalized gradient approximation to density functional theory has been used with an all electron basis set to study the stabilities of these structures. Dangling bond saturation of the Si atoms at both ends of the smaller clusters is needed to give them a smooth tubular shape. In general, harmonic frequency analyses indicate that the converged tubular structures are real minima, and not transition state structures. It follows that it is not necessary to have compounds (BN for example) that form two dimensional sheets for the existence of nanotubes. This may open up a new form of tubular configuration for the SiC nanotubes, as well as for other compounds.