空位缺陷对钇铝石榴石在高压下光学性质的影响

Influence of Vacancies on Optical Properties of Yttrium Aluminum Garnet under High Pressure

采用第一性原理方法,在120 GPa的压力范围内计算钇铝石榴石理想晶体和含氧空位缺陷晶体的光折射率和能量损失谱。获得的数据表明:在20 GPa以内,其折射率随压力的增加而降低;在20 GPa以上,其折射率随压力的增加而逐渐升高。另外,氧空位缺陷将引起其折射率明显减小。压力加载将导致其能量损失谱峰强度降低,且随压力逐渐增加还出现了蓝移的现象。同时,氧空位缺陷的存在使其峰值强度进一步减弱。文中的计算结果将为进一步的实验探究提供理论参考。

The optical refractive index and energy loss spectrum of yttrium aluminum garnet crystals without and with oxygen-vacancy defects were calculated using the first-principles method in the pressure range of 120 GPa.The obtained data show that:Within 20 GPa,its refractive index decreases with increasing pressure.Above 20 GPa,its refractive index increases gradually with increasing pressure.In addition,oxygen vacancy defects will lead to the decrease in refractive index significantly.The pressure loading will lead to a decrease in the peak intensity of its energy loss spectrum.It will also appear blue-shifting as pressure increases.At the same time,the presence of oxygen vacancy defects further weaken the peak intensity.The calculated results will provide some theoretical information for further experimental study.