Bao Shi-Yuan, Hong Dan, Lu Yi-Chen, Liu Qi-Jun, Liu Zheng-Tang, Zhang Jian-Qiong
Bond and Band Engineering Group, School of Physical Science and Technology, Southwest Jiaotong University, Chengdu, Sichuan, 610031, People's Republic of China.
State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an, 710072, People's Republic of China.
J Mol Model. 2022 Oct 13;28(11):360. doi: 10.1007/s00894-022-05352-z.
The vibrational, mechanical, electronic, and optical properties of the ε-O phase in the pressure range of 11.4-70 GPa were studied by the first-principle calculation method. The phonon dispersion curves have a tiny virtual frequency at 60 GPa, which indicates that ε-O is dynamically unstable at 60 GPa. However, the 3-BM EOS demonstrates that the unit cell is stable up to 70 GPa. It has been shown that ε-O remains ductile within the whole applied pressure range. Concurrently, we calculated the variation of the band gap of ε-O in the pressure range of 11.4-70 GPa. The results show that the band gap of ε-O decreases with increasing pressure. Notably, the band gap disappears within the range of 50-60 GPa, which reveals that the metallic phase transition occurs within this pressure range.
采用第一性原理计算方法研究了ε - O相在11.4 - 70 GPa压力范围内的振动、力学、电子和光学性质。声子色散曲线在60 GPa时出现微小的虚频，这表明ε - O在60 GPa时动力学不稳定。然而，3 - BM状态方程表明，直到70 GPa时晶胞都是稳定的。研究表明，ε - O在整个施加压力范围内均保持韧性。同时，我们计算了ε - O在11.4 - 70 GPa压力范围内带隙的变化。结果表明，ε - O的带隙随压力增加而减小。值得注意的是，带隙在50 - 60 GPa范围内消失，这表明在此压力范围内发生了金属相变。
