高压下钒的结构相变研究
Study on Structure Phase Transition of Vanadium under High Pressure
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摘要: 运用密度泛函理论研究了钒(Vanadium)在高压下的结构相变。 通过对体心立方(bcc)结构的钒在不同压强下剪切弹性系数C44的计算， 发现当压强约95 GPa时 C44＜0， 说明体心立方结构的钒在此条件下是不稳定的。 进一步计算分析得到钒在高压下发生了从体心立方到菱面体 (Rhombohedral)的结构相变， 相变压强约70 GPa， 这一结果与最近的实验结果符合。 还首次发现当压强约380 GPa时， 将会发生菱面体到体心立方的结构相变， 这有待实验的验证。
We have studied the structure phase transition of Vanadium under high pressures by density function theory. A mechanical instability in the shear elastic constant (C44) has been found for bodycentred cubic(bcc) Vanadium at about 95 GPa, which indicates the existence of the structural transition. By calculation and analysis, we found that there was a bccrhombohedral structure transition at the 70 GPa, which is consistent with the experiment data. Our calculations also firstly gave that there was a rhombohedralbcc structure transition at about 380 GPa, which needs to be verified by the experiment.Abstract: We have studied the structure phase transition of Vanadium under high pressures by density function theory. A mechanical instability in the shear elastic constant (C44) has been found for bodycentred cubic(bcc) Vanadium at about 95 GPa, which indicates the existence of the structural transition. By calculation and analysis, we found that there was a bccrhombohedral structure transition at the 70 GPa, which is consistent with the experiment data. Our calculations also firstly gave that there was a rhombohedralbcc structure transition at about 380 GPa, which needs to be verified by the experiment.
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