相变及空位缺陷对AlN在高压下光学性质的影响

采用基于密度泛函理论(DFT)的第一性原理方法, 计算了AlN理想晶体和含铝、氮空位点缺陷晶体在100 GPa压力范围内的光学性质. 波长在532 nm处的折射率计算结果表明：AlN从纤锌矿结构相转变为岩盐矿结构相将导致其折射率增加; 铝空位缺陷将引起AlN岩盐矿结构相的折射率增大, 而氮空位缺陷却导致其折射率降低. 能量损失谱计算数据指明：结构相变使得AlN能量损失谱蓝移、主峰峰值强度增强；铝和氮空位缺陷将导致AlN岩盐矿结构相的能量损失谱主峰进一步蓝移、峰值强度再次增强. 计算预测的结果将为进一步的实验探究提供理论参考.

Influence of phase transformation and vacancy defects on optical properties of AlN under high pressure

The first-principle methods based on density functional theory (DFT) were used to calculate the optical properties of AlN crystal without and with aluminum and nitrogen vacancy defects within 100 GPa . The refractive indexes at 532 nm show that: the wurtzite- to rocksalt- structural transition in AlN will lead to an increase in refractive index. Al-vacancy defects in the rocksalt-structural phase of AlN will cause an enhancement in its refractive index, but N-vacancy defects will lead to the decrease in refractive index. The loss-function spectrum data indicate that: both the structural phase-transition in AlN and the Al- and N-vacancy defects in its rocksalt-structural phase cause a blue-shift of its loss-function spectrum and an increase in the main-peak intensity. Our predicted results may be important for further experimental investigations.