Si-III (BC-8) crystal phase of Si and C: Structural properties, phase stabilities, and phase transitions
Si-III (BC-8) crystal phase of Si and C: Structural properties, phase stabilities, and phase transitions
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DOI：
10.1103/physrevb.30.1773
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发表时间：
1984-08
影响因子：
3.7
通讯作者：
M. Yin
中科院分区：
文献类型：
--
作者：
M. Yin
利用赝势局域密度泛函方法，计算了Si和Ci的Si-Ⅲ（BC-8）晶相的晶格常数、原子坐标的x参数和Γ 1+模的声子频率.计算结果与Si的BC-8相的实验数据吻合得很好。从金刚石和硅的BC-8相的总能量曲线可以看出，硅的BC-8相在常压和高压下都是不稳定的。Si的金刚石-BC-8（I-III）跃迁不是准静态发生的。比较金刚石、BC-8和C的简单立方相，我们发现在准静态条件下，金刚石在12 Mbar时首先转变为BC-8相，然后在27 Mbar时转变为简单立方相。
With use of the pseudopotential local-density-functional approach, the lattice constant, the x parameter for atomic coordinates, and the phonon frequency of the mode Γ 1+ are calculated for the Si-III (BC-8) crystal phases of Si and Ci. The results agree well with available experimental data for the BC-8 phases of Si. From the total-energy curves of the diamond and the BC-8 phases of Si, we find that the BC-8 phase of Si is not stable at ambient pressure or at high pressure. The diamond—BC-8 (I-III) transition of Si will not occur quasistatically. Comparing the diamond, the BC-8, and the simple-cubic phases of C, we find that diamond will first transform to the BC-8 phase at 12 Mbar and then to the simple-cubic phase at 27 Mbar under quasistatic conditions.