高压下XeF_2结构和电子性质的第一性原理研究

First-Principles Study of Structural and Electronic Properties of XeF_2 Crystal under High Pressure

二氟化氙(XeF2)晶体是一种重要的化学刻蚀材料和激光器件材料.利用密度泛函理论(DFT),分别采用广义梯度近似(GGA)和局域密度近似(LDA)对XeF2晶体在0～120 GPa范围内的结构进行相关分子动力学模拟,得到了压强-体积(p-V)关系.结果表明,低压下用2种方法得到的XeF2晶体数据与实验比较吻合.同时,分析了高压下原子态密度的变化,得到了XeF2晶体带隙与压强的变化关系,表明XeF2晶体在高压下是一种半导体材料.研究其在高压下的变化特征,对实验研究具有一定参考价值.

Xenon fluoride （XeF2） crystal is an important chemical etching and laser device material.In this paper pressure-volume （p-V） relationship of XeF2 crystals has been obtained in the range of 0 ～ 120 GPa using the molecular dynamics simulations,based on the generalized gradient approximation （GGA） and local density approximation （LDA） of density functional theory （DFT）.The results show that at the low pressure the crystal data of XeF2 gotten by two methods are in good agreements with experimental data.Meanwhile,changes of density of states of atoms under high pressure have been analyzed.The relationship between pressure and the band gap of XeF2 crystal has been obtained,indicating that XeF2 crystal is a semiconductor material under high pressure.Studying its variation under high pressure has a certain reference value for the experimental investigation.