  Metal catalysts supporting the growth of Single Wall Carbon Nanotubes display
different carbon solubilities and chemical reactivities. In order to
specifically assess the role of carbon solubility, we take advantage of the
physical transparency of a tight binding model established for Ni-C alloys, to
develop metal carbon models where all properties, except carbon solubility, are
similar. These models are used to analyze carbon incorporation mechanisms,
modifications of metal / carbon wall interfacial properties induced thereby,
and the associated nanotube growth mechanisms. Fine tuning carbon solubility is
shown to be essential to support sustainable growth, preventing growth
termination by either nanoparticle encapsulation or detachment.
