Stability in bcc Transition Metals: Madelung and Band-Energy Effects due to Alloying
2009 (English)In: Physical Review Letters, ISSN 0031-9007, Vol. 103, no 23, 235501- p.Article in journal (Refereed) Published
The phase stability of group VB (V, Nb, and Ta) transition metals is explored by first-principles electronic-structure calculations. Alloying with a small amount of a neighboring metal can either stabilize or destabilize the body-centered-cubic phase relative to low-symmetry rhombohedral phases. 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. In this case, the neighbor with less (to the left) and more (to the right) d electrons destabilize and stabilize bcc, respectively. When alloying with neighbors of higher d-transition series, electrostatic Madelung energy dominates and stabilizes the body-centered-cubic phase. This surprising prediction invalidates current understanding of simple d-electron bonding that dictates high-symmetry cubic and hexagonal phases.
Place, publisher, year, edition, pages
2009. Vol. 103, no 23, 235501- p.
IdentifiersURN: urn:nbn:se:uu:diva-127377DOI: 10.1103/PhysRevLett.103.235501ISI: 000272460200028OAI: oai:DiVA.org:uu-127377DiVA: diva2:329726