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

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、40GPa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、149GPa,这与实验结果接近。

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.