Compton scattering study on the electronic properties of niobium carbide and niobium nitride

Abstract

Abstract The electronic structure, experimental Compton profile and the chemical bonding mechanism of niobium carbide and niobium nitride are studied on the basis of the band structure calculations, using a self-consistent, all-electron, linear combination of Gaussian orbitals (LCGO) calculation based on density functional theory. Isotropic Compton profiles of niobium carbide have been measured, using a conventional technique based on 59.54 keV gamma-radiation with a solid state detector. The agreement between the experimental and the theoretical momentum density is very good. It is shown that the anisotropies at low momentum are heavily influenced by the particular shape of the Fermi surface. The charge distributions resulting from valence bands in different regions of the unit cell are discussed. The limitations of the rigid band structure model are illustrated and general trends in the chemical bonding are discussed.