Condensed Matter and Materials Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94551, USA.
Phys Rev Lett. 2009 Dec 4;103(23):235501. doi: 10.1103/PhysRevLett.103.235501.
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.
通过第一性原理电子结构计算探索 VB 族（V、Nb 和 Ta）过渡金属的相稳定性。与少量相邻金属合金化可以稳定或不稳定体心立方相对于低对称三方相。我们表明，当 VB 族特定金属与其在同一 d 过渡系列中的最近邻金属合金化时，能带结构效应决定了相稳定性。在这种情况下，具有较少（向左）和更多（向右）d 电子的近邻分别使 bcc 不稳定和稳定。当与更高 d 过渡系列的近邻合金化时，静电 Madelung 能占主导地位并稳定体心立方相。这一惊人的预测否定了目前对简单 d 电子键合的理解，该理解决定了高对称性立方和六方相。
