Ab initio calculations of elastic constants of the bcc V-Nb system at high pressures
2006 (English)In: Journal of Physics and Chemistry of Solids, ISSN 0022-3697, E-ISSN 1879-2553, Vol. 67, no 10-sep, 2056-2064 p.Article in journal (Refereed) Published
First-principles total energy calculation based on the exact muffin-tin orbital and full-potential linear muffin-tin orbital methods were used to calculate the equation of state and shear elastic constants of bcc V, Nb, and the V95Nb05 disordered alloy as a function of pressure up to 6 Mbar. We found a mechanical instability in C-44 and a corresponding softening in C at pressures similar to 2 Mbar for V. Both shear elastic constants show softening at pressures similar to 0.5 Mbar for Nb. Substitution of 5 at% of V with Nb removes the instability of V with respect to trigonal distortions in the vicinity of 2 Mbar pressure, but still leaves the softening of C-44 in this pressure region. We argue that the pressure-induced shear instability (softening) of V (Nb) originates from the electronic system and can be explained by a combination of the Fermi surface nesting, electronic topological transition, and band Jahn-Teller effect.
Place, publisher, year, edition, pages
2006. Vol. 67, no 10-sep, 2056-2064 p.
metals, ab initio calculations, elastic properties, electronic structure, fermi surface, reduced lattice spacings, muffin-tin orbitals, electronic-structure, brillouin-zone, band calculations, special points, fermi-surface, energy-bands, vanadium, niobium
IdentifiersURN: urn:nbn:se:kth:diva-16037DOI: 10.1016/j.jpcs.2006.05.027ISI: 000241089600022ScopusID: 2-s2.0-33748150946OAI: oai:DiVA.org:kth-16037DiVA: diva2:334079
QC 20100525 QC 20110927. Conference: Conference on Study of Matter at Extreme Conditions (SMEC2005). Miami Beach, FL. APR 17-21, 2005 2010-08-052010-08-052011-09-27Bibliographically approved