Theory of Structural and Electronic Properties of Silicon Nitride and Carbon Nitride

Abstract

ABSTRACTUsing a first principles pseudopotential total energy approach with a localized basis for the electronic wave functions, we have investigated the structural and bonding properties of β-Si3N4 and β-C3N4, which is a proposed structure for carbon nitride. The latter system is used as a prototype for studying the properties of possible covalent C-N solids. For β-Si3N4, calculated structural properties such as lattice constant and bulk modulus are in excellent agreement with experimental values. This gives support for the predicted properties of β-C3N4.β/C3N4 is found to be a good candidate for a new low-compressibility solid, with compressibility comparable to diamond. Despite similarities between β-Si3N4 and β-C3N4 in terms of crystal structure and valency of constituent elements, differences are found in their electronic bonding properties. A comparison of the bonding in β-Si3N4 and β-C3N4 with other first and second row semiconductors is useful for understanding trends in the structural properties of these materials.