Microscopic analysis of interatomic forces in transition metals with lattice distortions
Microscopic analysis of interatomic forces in transition metals with lattice distortions
复制标题
具有晶格畸变的过渡金属中原子间力的微观分析
DOI：
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发表时间：
1983
期刊：
影响因子：
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通讯作者：
B. Harmon
中科院分区：
文献类型：
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作者：
K. Ho;C. Fu;B. Harmon
现在，利用冷冻声子方法完全从第一性原理计算过渡金属的精确振动频率是可能的。此外，利用赫尔曼-费曼定理，可以计算出由电子对特定声子畸变的响应引起的原子间力。对这些力的分析有助于可视化造成声子异常的复杂微观相互作用。对Mo、Nb和bcc Zr中重要的纵向声子（$frac{2}{3}$,$frac{2}{3}$,$frac{2}{3}$）进行了技术和分析。随着电子原子比从Nb到Mo的增加，这种模式的强化是由定向键的发展引起的。Zr的高温bcc相在此模式下的急剧倾斜和bcc Zr对$ensuremath{omega}$相形成的不稳定性与$d$-电子筛选和电子结构的细节有关。
It is now possible to calculate accurately vibrational frequencies for transition metals entirely from first principles using the frozen-phonon approach. In addition, the interatomic forces arising from the electronic response to a particular phonon distortion can be calculated by making use of the Hellmann-Feynman theorem. Analysis of these forces helps in visualizing the complicated microscopic interactions responsible for phonon anomalies. The techniques and analysis are demonstrated for the important longitudinal ($frac{2}{3}$,$frac{2}{3}$,$frac{2}{3}$) phonon in Mo, Nb, and bcc Zr. The stiffening of this mode as the electron-per-atom ratio increases from Nb to Mo is shown to arise from a development of directional bonding. The precipitous dip in this mode for the high-temperature bcc phase of Zr and the instability of bcc Zr towards the formation of the $ensuremath{omega}$ phase are related to the $d$-electron screening and details of the electronic structure.