Abstract
The electronic structure of the high-temperature rutile phase of Nb is studied by the linearized-augmented-plane-wave method. Potentials constructed by superposition of neutral-atom and ionic-charge densities are used to explore variability of the electronic band structure. A rigid-band scheme is shown to accurately describe optical absorption of the rutile phase of Nb stabilized by the addition of 20 at.% Ti as measured by Raccah et al. Differences between the band results for rutile Nb and the optical absorption measurements on the low-temperature body-centered tetragonal phase of Nb are attributed to band splittings induced by lattice distortion which occur at the phase transition. The static-electron response function is calculated in the constant-matrix-elements approximation. In contrast to the case of isoelectronic V, no Fermi-surface nesting features are observed, and is found to be structureless in the vicinity of the point which has been associated with a possible soft-mode phonon instability responsible for the lattice transformation.
- Received 29 January 1979
DOI:https://doi.org/10.1103/PhysRevB.19.6555
©1979 American Physical Society