Electronic structure and elastic moduli of the simple cubic fullerite C24—A new allotropic carbon modification

Autor: V. V. Pokropivny, V. L. Bekenev
Rok vydání: 2006
Předmět:
Zdroj: Physics of the Solid State. 48:1405-1410
ISSN: 1090-6460
1063-7834
DOI: 10.1134/s1063783406070298
Popis: The energy band structure, equation of state, density of states, and elastic moduli of a new allotropic carbon modification, namely, fullerite C24 with a simple cubic lattice (known previously as cubic graphite), are calculated by the full-potential linearized augmented-plane-wave (FLAPW) method with geometry optimization for the first time. The dependence of the total energy on the lattice constant exhibits a minimum for a0 = 0.60546 nm. In this case, the lengths of the C-C bonds between fullerene molecules, the lengths of the 6,6-bonds shared by hexagons, and the lengths of the 4,6-bonds shared by a square and a hexagon are equal to 0.1614, 0.1503, and 0.1637 nm, respectively. An analysis of the energy band structure and the density of states demonstrates that the simple cubic fullerite C24 is a direct-band-gap insulator or a semiconductor with a band gap of 1.6 eV. The calculated bulk modulus B0 = 196 GPa and the elastic moduli C11 = 338 GPa, C12 = 139 GPa, and C44 = 30 GPa indicate that the fullerite under investigation is a mechanically stable material. The inference is made that the simple cubic fullerite C24 is a new diamond-like molecular zeolite with a unique combination of properties, such as the porosity and nonpolarizability, on the one hand, and the mechanical strength, chemical inertness, and high thermal conductivity, on the other hand. The simple cubic fullerite C24 can be considered a promising low-dielectric-constant (low-k) material (ɛ0 < 5.7) for use in fabricating interconnections and substrates intended for integrated circuits and nanoelectronics.
Databáze: OpenAIRE
Externí odkaz: