高压下XeF_2结构稳定性及电子结构性质的理论研究

Theoretical research on structural stability and electronic structure of XeF_2 under high pressure

采用平面波赝势密度泛函理论方法研究了惰性气体化合物XeF2在0~80GPa压力范围内的结构性质,计算值与实验值相符合.根据我们计算得到的不同压力XeF_2的弹性常数,结合力学稳定性判据,证实XeF_2的I4/mmm结构在80GPa压力范围内是稳定的.计算了不同压力下XeF_2的带隙,发现带隙随着压力的增大而减小.当压力大于10GPa时,XeF_2的带隙随压力的增大近似呈线性减小趋势.表明随着压力的增大XeF_2晶体由绝缘体向半导体转变,且金属性越来越强.

The structural properties of XeF2 in the pressure range from 0 to 80 GPa are studied by plane- wave pseudopotential density functional theory method. The calculated values are in agreement with the experimental data. Based on the calculated elastic constants of XeF2 under different pressures, the 14/ mmm structure of XeF2 is confirmed to be stable in the pressure range from 0 to 80 GPa. The band gaps of XeF2 at different pressure are calculated and the band gap is found to decrease with the increase of pressure. When the pressure is greater than 10 GPa the band gap of XeF2 increases linearly with the in- crease of pressure, which indicates that XeF2 transforms from the insulator to semiconductor and has more and more strong metallic with the increase of pressure.