Non-traditional carbon semiconductors prepared from fullerite C60 and carbyne under high pressure

We present the detailed study of X-ray diffraction, Raman and absorption edge spectra, mechanical, and transport properties of new metastable carbon phases prepared from fullerite C-60 and cumulene carbyne by high-pressure-temperature treatment and also review some recent relevant results. The sequence of phases obtained gives the picture of temperature-induced. transformations under pressure, which are described in terms of covalent bonding of C-60 molecules or cumulene chains in carbyne. Special attention is paid to the three-dimensional polymerization of fullerite C-60 Experimental data suggest certain relations between the physical properties of prepared carbon phases, the majority of which are semiconductors, and the bonding nature of materials, i.e., the number of atoms in differently hybridized carbon states, structure topology, contribution of van der Waals interaction, etc.