Structure, electronic and elastic properties of the NbRu shape memory alloys
Department of Physics, University of Jordan, Amman, 11942, Jordan
Corresponding author: a email@example.com
Revised: 26 September 2009
Published online: 7 November 2009
The phase stability and electronic structure of NbRu shape memory alloys are studied by self-consistent full-potential linearized augmented plane wave method (FP-LAPW) on the basis of the density functional theory (DFT). The calculated equilibrium volumes are about 32 Å3 and 30 Å3 for β-, β′ and β′′ phases using the generalized gradient approximation (GGA) and local density approximation (LDA), respectively, which are in good agreement with the experimental values. The β′′-phase is favored by about 65 meV/formula than the β-phase. The value of the density of states at the Fermi energy, confirms that the β′′ phase is the ground state equilibrium phase of NbRu at low temperatures, in agreement with the experimental findings. Our results put an end to the experimental debate regarding the β′′ phase whether it is orthorhombic or monoclinic. By optimizing the angle γ, we found that the β′′ structure is monoclinic of (P21/m) symmetry.
PACS: 71.15.-m – Methods of electronic structure calculations / 71.20.-b – Electron density of states and band structure of crystalline solids
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2009