Phase stability in α- and β-rhombohedral boron
Phase stability in α- and β-rhombohedral boron
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DOI：
10.1103/physrevb.75.092101
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发表时间：
2007-03-01
影响因子：
3.7
通讯作者：
Liu, Zi-Kui
中科院分区：
文献类型：
--
作者：
Shang, Shunli;Wang, Yi;Liu, Zi-Kui
用第一性原理准谐波声子计算研究了α -和β - b的相稳定性。结果表明，在1388 K以下，无缺陷的α - b比无缺陷的β - b更稳定。结果表明，无缺陷的β -B在高温下（高于1840 K）是机械不稳定的，这可以通过引入缺陷（例如额外的B原子）来抑制假想声子模式的出现。这一发现与实验观察一致，即缺陷通常发生在β - b中。
Phase stability in alpha- and beta-B has been investigated by using first-principles quasiharmonic phonon calculations. It is found that the defect-free alpha-B is more stable than the defect-free beta-B at lower temperatures up to the predicted 1388 K. It is revealed that the defect-free beta-B is mechanically unstable at high temperatures (above 1840 K), indicated by the appearance of imaginary phonon modes, which can be suppressed by introducing defects, e.g., the extra B atoms. This discovery is consistent with the experimental observations that defects occur commonly in beta-B.