  Structural, elastic and electronic band structure properties of A-15 type
Nb-based intermetallic compounds Nb3B (B = Os, Pt, Au) have been revisited
using first principles calculations based on the density functional theory
(DFT). All these show excellent agreement with previous reports. More
importantly, electronic bonding, charge density distribution and Fermi surface
features have been studied in detail for the first time. Vickers hardness of
these compounds is also studied. The Fermi surfaces of Nb3B contain both hole-
and electron-like sheets, the features of which change systematically as one
move from Os to Au. The electronic charge density distribution implies that
Nb3Os, Nb3Pt and Nb3Au have a mixture of ionic and covalent bondings with a
substantial metallic contribution. The charge transfer between the atomic
species in these compounds has been explained via the Mulliken bond population
analysis and the Hirshfeld population analysis. The bonding properties show a
good correspondence to the electronic band structure derived electronic density
of states (DOS) near the Fermi level. Debye temperature of Nb3B (B = Os, Pt,
Au) have been estimated from the elastic constants and show a systematic
behavior as a function of the B atomic species. We have discussed implications
of the results obtained in this study in details in this paper.
