Alloying-driven phase stability in group-VB transition metals under compression
2010 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 82, no 14, 144114- p.Article in journal (Refereed) Published
The change in phase stability of group-VB (V, Nb, and Ta) transition metals due to pressure and alloying is explored by means of first-principles electronic-structure calculations. It is shown that under compression stabilization or destabilization of the ground-state body-centered-cubic (bcc) phase of the metal is mainly dictated by the band-structure energy that correlates well with the position of the Kohn anomaly in the transverse-acoustic-phonon mode. The predicted position of the Kohn anomaly in V, Nb, and Ta is found to be in a good agreement with data from the inelastic x-ray or neutron-scattering measurements. In the case of alloying the change in phase stability is defined by the interplay between the band-structure and Madelung energies. We show that band-structure effects determine phase stability when a particular group-VB metal is alloyed with its nearest neighbors within the same d-transition series: the neighbor with less and more d electrons destabilize and stabilize the bcc phase, respectively. When V is alloyed with neighbors of a higher (4d- or 5d-) transition series, both electrostatic Madelung and band-structure energies stabilize the body-centered-cubic phase. The opposite effect (destabilization) happens when Nb or Ta is alloyed with neighbors of the 3d-transition series.
Place, publisher, year, edition, pages
2010. Vol. 82, no 14, 144114- p.
IdentifiersURN: urn:nbn:se:kth:diva-26250DOI: 10.1103/PhysRevB.82.144114ISI: 000283220100011ScopusID: 2-s2.0-78049469980OAI: oai:DiVA.org:kth-26250DiVA: diva2:397262
FunderSwedish Research Council
QC 201102142011-02-142010-11-212011-02-14Bibliographically approved