In this paper, we used the density functional theory based on GGA-PBE approximation, to reconsider the stability of CaH₆ in phase cI14, which corresponds to the superconducting state according to some theoretical study. Our motivation for reconsidering is the conflict between an experimental and theoretical result about the stability of CaH₆ in the superconducting phase under high stress. The obtained results of the elastic constants at a wide range of pressures indicated the mechanical instability of CaH₆ in the cI14 prototype. The phonon spectrum showed positive frequencies at pressures higher than 150 GPa, which correspond to dynamic stability.

在本文中，我们使用基于 GGA-PBE 近似的密度泛函理论，重新考虑 CaH ₆在 cI14 相中的稳定性，根据一些理论研究，该相对应于超导状态。我们重新考虑的动机是关于高应力下超导相中CaH ₆稳定性的实验和理论结果之间的冲突。在很宽的压力范围内获得的弹性常数结果表明cI14 原型中 CaH ₆的机械不稳定性。声子谱在高于 150 GPa 的压力下显示出正频率，这对应于动态稳定性。