Formation of, and ion-transport in, low-dimensional crystallites in carbon nanotubes

Abstract

The formation of low-dimensional crystal structures, obtained by filling carbon nanotubes from the molten salts, is considered for three stoichiometries (the MX, MX₂ and MX₃). For the MX stoichiometry, general classes of inorganic nanotube (INT) are predicted to exist whose morphology depends both on the low-energy (bulk) crystal structure and the encasing carbon nanotube diameter. These INTs are generally found to have no direct bulk analogues. For both the MX₂ and MX₃ stoichiometries crystal structures are predicted which either have a direct bulk analogue, or whose structure can be considered as a distortion of a bulk fragment. In both of these stoichiometries unusual (high anion coordination) crystallites are predicted. For the MX stoichiometry the ion transport mechanism is investigated and discussed, whilst for the MX₃ the vibrational densities of states are analysed with respect to both the pure liquid and idealized crystallites.