高压下惰性气体晶体的第一性原理研究

First Principles Study of Rare-Gas Solids Under High Compression

摘要: 利用第一性原理，研究了惰性气体晶体的晶体结构和非金属-金属转变。晶体的焓差显示：氦、氖晶体在高压下未发生结构相变，分别保持六角密堆积结构和面心立方；而氩、氪、氙晶体分别在192、95、40 GPa从面心立方结构转变为六角密堆积结构。通过研究惰性气体晶体的能带随压强的变化，发现氦、氖、氩、氪、氙的非金属金属转变压强分别为22 000、319 000、578、365、149 GPa，这与实验结果接近。

Abstract: Crystal structures and metallization of the rare-gas solids at high pressures were studied with the first principles. The enthalpy differences of the rare-gas solids show that no phase transition occurs for He and Ar, while Ne, Kr, Xe undergo a phase transition from the fcc to the hcp structure at pressures of about 192, 95 and 40 GPa, respectively. From the band gaps, we found that the insulator-metal transition for He, Ne, Ar, Kr and Xe should occur around 22 000, 319 000, 578, 365, and 149 GPa, respectively.