Computation of structure and electronic properties of hybrid phase formed by polymerization of C${}_{20}$ fullerenes

The geometrically optimized structure and electronic properties of a new hybrid carbon phase consisting of carbon atoms in three- and four-coordinated (sp${}^2$+sp${}^3$ hybridized) states are calculated. The calculations are performed by the method of density functional theory in the gradient approximation. The initial phase structure was constructed with partial crosslinking of fullerite C${}_{20}$. The calculated sublimation energy sp${}^2$+sp${}^3$ of 6.92 eV/atom structure is less than the sublimation energies of graphite and cubic diamond, however, falls within the range of values characteristic for carbon materials that persist under normal conditions. The density of electron states at the level of the Fermi energy of this phase is zero and its properties should be metallic.