Electronic band structure of 3C-SiC from extended Huckel theory

Calculations are performed on cubic SiC by using the extended Huckel method. Crystalline silicon and diamond are also considered. It is shown that the inclusion of excited (s*) atomic orbitals in the basis set, a suggestion recently made in the literature, as well as a convenient change in a few valence shell empirical parameters provide a good description of valence and conduction bands, in particular giving rise to the appearance of the indirect gap. The parametrization of valence orbitals is shown to have physical justification and its generality is stressed. A good agreement of cubic SiC band structure results when crystalline silicon and diamond parameters an used together with a scaling transformation according to the crystal lattice parameters. The independent choice of s* parameters in all three materials is discussed. (C) 1999 Elsevier Science B.V. All rights reserved.