Alloying-driven phase stability in group-VB transition metals under compression

作     者：A. Landa P. Söderlind O. I. Velikokhatnyi I. I. Naumov A. V. Ruban O. E. Peil L. Vitos 

作者机构：Condensed Matter and Materials Division Physical and Life Sciences Directorate Lawrence Livermore National Laboratory Livermore California 94551 USA Department of Bioengineering University of Pittsburgh Pittsburgh Pennsylvania 15261 USA Information and Quantum Systems Laboratory Hewlett-Packard Palo Alto California 94304 USA Department of Materials Science and Engineering Applied Materials Physics Royal Institute of Technology SE-100 44 Stockholm Sweden Institute of Theoretical Physics University of Hamburg 20355 Hamburg Germany Department of Physics and Materials Science Division for Materials Theory Uppsala University SE-75121 Uppsala Sweden 

出 版 物：《Physical Review B》 (物理学评论B辑：凝聚态物质与材料物理学)

年 卷 期：2010年第82卷第14期

页      面：144114-144114页

核心收录：

学科分类：07[理学] 0702[理学-物理学] 

基　　金：U.S. DOE [DE-AC52-07NA27344] Swedish Research Council 

摘      要：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.