高压下氟化钙的多晶型与单晶型
Superionicity and Polymorphism in Calcium Fluoride at High Pressure
摘要：
我们提出了一个相结合的实验和计算的第一性原理研究的超离子和结构性质的CaF 2在高P-T条件。我们观察到一个异常的超离子行为在低磷萤石相，包括在正常->超离子临界温度的压缩降低。这种意想不到的效果可以解释的P-诱导软化的区域边界$X$声子，其中涉及专门氟位移。此外，我们发现，超离子导电性是不存在的高P cotunnite相。相反，超离子性发展在一个新的低对称性高T相，我们确定为单斜（空间群P2_1/c）。我们讨论了观察这些有趣的现象在相关的同构材料的可能性。
英文摘要：
We present a combined experimental and computational first-principles study of the superionic and structural properties of CaF2 at high P-T conditions. We observe an anomalous superionic behavior in the low-P fluorite phase that consists in a decrease of the normal-> superionic critical temperature with compression. This unexpected effect can be explained in terms of a P-induced softening of a zone-boundary $X$ phonon which involves exclusively fluorine displacements. Also we find that superionic conductivity is absent in the high-P cotunnite phase. Instead, superionicity develops in a new low-symmetry high-T phase that we identify as monoclinic (space group P2_1/c). We discuss the possibility of observing these intriguing phenomena in related isomorphic materials.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
